bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Incidence of Hypertension in Type II Diabetes and It’s Correlation
Authors: Prihantini Nur Nunu , Kurniyanto  , Putri Putu Moradha Kharisma
Published: February 2025

Aims:  to evaluate the relationship between Type 2 Diabetes Mellitus (T2DM) patients and the incidence of hypertension at the Indonesian Christian University Hospital from 2020-2022.
Study Design: The design used in this study was analytical and observational. The approach is cross-sectional, data collection uses medical records of patients registered at the Indonesian Christian University RSU in 2020-2022.
Place and Duration of Study: The location of data collection was carried out at the Christian University RSU Indonesia which will be held in May 2024.
Methodology: The population in this study were all diabetes mellitus patients with either outpatient or inpatient status hospitalized at the Indonesian Christian University General Hospital 2020–2022, while samples were taken using a total sampling technique with a total sample of 112 patients. Data collection took the form of secondary data, namely medical records of T2DM patients at the Indonesian Christian University General Hospital for the period 2020-2022.
Results: The results showed that 80.4% of patients suffered from T2DM, while 19.6% did not suffer from DM. The highest prevalence of hypertension patients was in grade 1 hypertension, which was 63.4%. In addition, the age group ≥ 66 years has the highest prevalence of hypertension at 40,7%, and female gender dominates with 66,3% of hypertensive patients. Statistical analysis using the Chi-square test showed a significant relationship between T2DM and hypertension (p = 0.000). However, 71,4% of the T2DM patient group experienced more hypertension than Non-DM patients.
Conclusion: Based on these results, although there is a statistical relationship between T2DM and the incidence of hypertension, age, and gender factors still have a significant effect on the prevalence of hypertension. That indicates the need for further monitoring of high-risk patients with hypertension, especially among T2DM patients.
Strengthening Parasitic Infection Prevention and Control Practices: An Aspect of Health Promotion
Authors: Siagian Forman Erwin
Published: February 2025

Aims: to describe aspects of specific health promotion which will strengthening parasitic infection prevention and control practices.
Discussion: Health promotion is a dynamic and continuous process of enabling people to have increase control over and to improve their own health by finding the root causes of health problems and its underlying condition and to overcome barriers and also to improve aspects of socioeconomic, level of knowledge, environmental improvement, political and legislative arrangement and even law enforcement if necessary. Those aspects, which also work in the case of Parasitic diseases such as malaria and STH, are important part of early intervention and disease prevention and can be used to help build social and physical environments that support healthy behaviors. Health promotion approach for parasitic disease is always specific and based on the existing knowledge regarding the parasite’s life cycle and its existence in nature and interaction with other organism inhabitants of the same environment.
Conclusion: The complexity of specific health promotion regarding parasitic infection, in which programs to control or eliminate parasitic diseases are positioned, and the development of better understanding regarding its contributing factors are still a major issue in parasite disease control. The competition for resources in the health as well as other social sectors will be a continuing challenge; effective parasite control will be dependent on how such resources are accessed and deployed to effectively address well-defined problems some of which are readily amenable to successful interventions with proven methods. Failure to sustain control of parasites is always a threat for the society, but health promotion and health education is always being a primary option to prevent parasite transmission, controlling the parasitic epidemiology and followed by the establishment of better healthy community.
Effects of Rock Phosphate, Farmyard Manure, and Vermicompost on Growth, Yield, and Soil Quality in Field Cultivation of Chickpea
Authors: Rinku  , Singh Satyavir , Kumar Awanish , Dayal Guru , Kushwaha Raghvendra Kumar
Published: February 2025

The study was carried out to find out the effect of Rock phosphate and organic manures on growth, yield and soil quality of chickpea cultivation and suitable doses of FYM, Vermicompost and Rock Phosphate for Chickpea. The Field experiment was conducted at organic research farm Karguan Ji, Institute of Agricultural Sciences, Bundelkhand University Jhansi (UP), India during rabi season of 2023-2024.  The experiment was laid out in randomized block design comprises Three levels of rock phosphate (200, 300 and 400 kg/ha) and two levels of FYM and Vermicompost (100% and 50%) with three replications. The application of FYM, Vermicompost and Rock phosphate were obtained significantly higher values in respect to growth, yield attributes and soil quality of chickpea in all the treatments, over control. The highest values were recorded in respect ofplant height (36.37cm), number of branches/plants (11.48), number of pods/plants (99.92), number of seeds/pods (2.67), grain yield (15.57 q/ha), stover yield (21.26 q/ha), biological yield (36.84 q/ha), 100 seed weight (17.91gram) and harvest index (43.54%).Soil pH: Ranged from 6.23 (T1 and T7) to 6.70 (T2 and T5). Soil Electrical Conductivity (Ec): Ranged from 0.49 dS/m (T5) to 0.65 dS/m (T6).Soil Organic Carbon (OC): Ranged from 0.61% (T0) to 0.94% (T7).Available Nitrogen (N): Ranged from 86.77 kg/ha (T0) to 155.57 kg/ha (T7).Available Phosphorus (P): Ranged from 11.07 kg/ha (T0) to 21.50 kg/ha (T4).Available Potassium (K): Ranged from 155.90 kg/ha (T0) to 201.93 kg/ha (T6).Available Sulphur (S): Ranged from 9.25 Mg/kg (T0) to 19.90 Mg/kg (T4).The combined application of FYM, vermicompost, and rock phosphate significantly enhanced chickpea growth, yield, and soil nutrient availability, demonstrating the potential for improved and sustainable agricultural practices. These findings align with previous research indicating the beneficial effects of organic amendments on soil and plant health.
WSSV Genotypes in Shrimp Aquaculture in Kerala, India Employing Variable Number Tandem Repeat in DNA Segments
Authors: P.G. Akhilnath , P. Shaheer. , P. S. Reethy , V. Murugadas , Joseph Toms C. , Lalitha K.V.
Published: February 2025

Disease caused by White spot syndrome virus (WSSV) is a major problem for the shrimp farming industry in India. Monitoring for the distribution and makeup of WSSV genotypes is thus important for identifying virus entry routes and developing strategies to avoid economic losses. Here variable number tandem repeat (VNTR) loci were analyzed to identify the variability and potential origins of WSSV genotypes occurring in shrimp farmed in Kerala. In total, 434 shrimp were screened by PCR. The study revealed that genetic characteristics of Taiwan, Indian and Chinese WSSV were prevalent in Kerala based on VNTR. Samples that are positive for WSSV in both first and second PCR itself were unable to produce amplifications for ORF94, 125 and75. This may be due to the sequence variation at the primer binding site. The potential use of VNTR loci analysis for the source tracking of WSSV in the various shrimp production system and recommends for bigger surveillance on genotyping to identify the unknown source of origin for better visualization of the distribution of shrimp.
Digital Technology in Agribusiness of North East India
Authors: Maring Th Onchoila , Devarani Loukham , Kumar Pankaj
Published: February 2025

The Indian economy relies significantly on agriculture, employing around 42.3% of the workforce and contributing 18.2 % to the GDP in the financial year 2023-24. However, the sector faces challenges due to the fragmentation of farmlands, with 89.4% cultivated by small and marginal farmers who own less than 2 hectares of land. To address these issues for improving farmers' livelihoods, forming Farmer Producer Organizations (FPOs) has emerged as a promising solution. These organizations bring together individual farmers, enabling economies of scale and enhancing their income prospects. In recent years, the integration of digital technology has played a crucial role in strengthening FPOs and addressing various challenges. Moreover, digital services have facilitated capacity building among farmers but progress in digitization in the North East Region (NER) of India has been slow compared to other parts of the country. To gain insight into the usage of digital technology by FPOs and agripreneurs in the NER, a study was conducted during the 1stNorth East Conclave held at CPGS-AS, CAU (I), Umiam, Meghalaya. A sample of 22 respondents was selected based on convenience sampling. Primary data was collected through a semi-structured interview schedule and descriptive statistics was used to analyse the obtained data. To gain a better understanding of the prevailing scenario, various data from secondary sources were also studied. The study found that mobile phones were the participants most widely used digital tools. The SWOT analysis of digital technology highlighted strengths such as high mobile phone penetration. On the other hand, weaknesses included low e-literacy levels and limited internet connectivity. Opportunities identified were related to digital marketing, remote monitoring, and advisory services, while threats included rapid technological changes, duplication, and contradictory information flow. Based on the study's findings, the way forward involves investing in improving digital infrastructure, particularly internet connectivity, to ensure seamless access to digital solutions for farmers. Establishing regional e-commerce platforms can directly connect farmers with buyers, eliminating intermediaries and empowering farmers with better market access. These steps can contribute to the modernization and digitization of agricultural practices in rural India, ultimately leading to improved livelihoods and income augmentations for farmers in the NER.
Biofilm on catheters associated with bloodstream infections in the Intensive Care Unit / Biofilme em cateteres associados a infecções de corrente sanguínea na unidade de terapia intensiva
Authors: Pereira Victor Daniel Ribeiro , Farias Karol Fireman de , Santos Ana Caroline Melo dos
Published: February 2025

Objetivo: avaliar a prevalência de microrganismos em infecções da corrente sanguínea relacionadas ao uso de cateteres venosos centrais em pacientes adultos de UTI, destacando os patógenos mais prevalentes, os fatores de risco e as medidas preventivas. Método: revisão integrativa da literatura, com busca em bases de dados eletrônicas como Science Direct, PubMed, SciELO, CAPES e Biblioteca Virtual em Saúde (BVS), abrangendo o período de 2020 a 2024. Resultados: 1.364 artigos foram identificados, sendo 14 incluídos para análise. Staphylococcus epidermidis, Klebsiella pneumoniae e Acinetobacter baumannii foram os patógenos mais prevalentes em biofilmes de cateteres. O uso prolongado de CVCs, especialmente por mais de 15 dias, foi associado a uma maior incidência de infecções. A resistência antimicrobiana, especialmente entre patógenos Gram-negativos, foi significativa, complicando o tratamento dessas infecções. Conclusão: a formação de biofilmes em CVCs está associada a infecções graves em pacientes de UTI, com predominância de microrganismos resistentes a múltiplos fármacos.
Strength Training Applied To Knee Rehabilitation After Anterior Cruciate Ligament Injury: Integrative Review
Authors: Melo Valquiria Oliveira , Barreto Patric Roberto Ferreira , Sousa Ronny Batista De , Silva Natanael Magno , Silva João Pedro Sousa Farias , Sousa Maria Flávia De
Published: February 2025

Anterior cruciate ligament (ACL) injuries occur more frequently in daily activities, both in everyday life and
sports. The present study aimed to investigate the effects of strength training in the rehabilitation of the knee
following anterior cruciate ligament (ACL) injury. An integrative review was conducted in the months of April
to May 2023, with a temporal delineation from January 2018 to December 2022. The search was performed in
secondary databases, the Virtual Health Library, such as (SCIELO), (LILACS), and (MEDLINE). Article
selection was carried out using the following descriptors, generated through the Health Sciences Descriptors
(DeCS) platform, in the Medical Subject Headings (MeSH), and employing boolean operators "AND" and
"OR": Knee Injuries AND Strength Training AND Anterior Cruciate Ligament Injuries AND Rehabilitation OR
Exercise Therapy. A total of 145 publications were identified, and after applying inclusion and exclusion
criteria, 8 studies were deemed eligible. The study demonstrated that while strength training with eccentric
overload showed greater muscle hypertrophy, potentially beneficial for increasing muscle mass in athletes, it
could result in a less favorable muscular phenotype for rapid and explosive movements crucial in certain sports
activities. In conclusion, long-term research, evaluation of specific performance variables, direct comparisons between training methods, personalized adaptation, and multidisciplinary interventions are suggested to optimize post-ACL injury recovery.
Atendimento Multiprofissional Na Rede De Atenção A Saúde E Sofrimento Mental Em Pessoas Em Situação De Rua: Revisão Narrativa
Authors: Sousa Ronny Batista De , Da Silva Natanael Magno , Mesquita Eliana Mendes , Sousa Francisco Alves De , Santos Silva Francisco Canindé Dos , Franco Cassandra Maria Bastos
Published: February 2025

Este estudo teve como objetivo analisar as evidências disponíveis sobre o atendimento multiprofissional na
rede de atenção à saúde e o sofrimento mental em pessoas em situação de rua, por meio de uma revisão
narrativa da literatura. A busca foi realizada em bases de dados eletrônicas, resultando em 85 estudos
inicialmente identificados, dos quais 8 foram selecionados para análise final. Os resultados revelaram que a
personalização do cuidado, a integração das abordagens multiprofissionais e a consideração das condições
psicossociais dos pacientes são fatores essenciais para o sucesso das intervenções. A coordenação entre
profissionais de diversas áreas, como psicólogos, assistentes sociais, médicos e enfermeiros, foi destacada
como crucial para garantir um atendimento mais humanizado e integral. No entanto, a falta de recursos, a
fragilidade das redes de cuidado e a escassez de capacitação específica das equipes de saúde ainda
representam barreiras significativas para a implementação efetiva das abordagens personalizadas. A revisão
também indicou que a criação de políticas públicas adequadas, voltadas para a integração dos serviços de
saúde e sociais, é fundamental para melhorar o atendimento a essa população vulnerável. Conclui-se que,
apesar dos avanços, ainda existem desafios estruturais e operacionais a serem superados para garantir a
efetividade do cuidado multiprofissional e personalizado, sendo necessário investir em infraestrutura, capacitação contínua e políticas públicas intersetoriais para promover a inclusão social e o bem-estar de pessoas em situação de rua.
Soluble carbohydrates in Delphinium and their influence on sepal abscission in cut flowers
Authors: Ichimura Kazuo , Kohata Katsunori , Goto Rie
Published: July 2002

A carbohydrate other than sucrose, glucose, fructose and myo‐inositol was detected in sepal extracts of Delphinium. This compound was identified as mannitol by 1H‐NMR. Mannitol was the major carbohydrate in all examined organs: the sepal, the other parts of the flower, the stem and leaves. Mannitol as well as glucose (both at 0.55 M), fed to cut Delphinium flowers, similarly delayed the abscission of sepals. 3‐O‐methyl glucose (3‐OMG) and polyethylene glycol 200 at the same molar concentrations had no such effect. The treatment with glucose markedly increased the concentrations of glucose and fructose in the sepals without changing the concentrations of sucrose and mannitol. On the other hand, the treatment with mannitol increased the concentrations of glucose and fructose in addition to mannitol in the sepals, suggesting that mannitol is metabolized in Delphinium flowers. The treatment with 3‐OMG increased the concentration of 3‐OMG but not other carbohydrates. Mannitol and glucose similarly delayed the increase in ethylene production in flowers, but 3‐OMG did not. The sensitivity to ethylene was similarly reduced by the treatment with glucose and mannitol, but not by 3‐OMG. These results suggest that the treatment with mannitol, a major carbohydrate in Delphinium, delayed the abscission of sepals by reducing the sensitivity to ethylene. Mannitol further acted, not merely as an osmolyte, but as an apparent source for carbohydrate metabolism in the flower.
Bilateral investigation of the temporomandibular joint. An autopsy study of edentulous individuals
Authors: Grunert I. , Grubwieser G. J. , Ulmer H.
Published: July 2002

Investigations concerning normal and pathological anatomy of the temporomandibular joint (TMJ) have shown that pathological reactions such as deviations of the shape of the condyle, disc thinnings, disc perforations and osteoarthrotic changes are fairly common, particularly in the elderly population. Autopsy studies of the TMJ describe pathological findings respective to their location in different age groups, but most authors describe their findings for removed joints of one side only. The specific aim of this study was therefore to investigate the intra‐individual relationships between the degenerative changes and deviations concerning the articular surfaces of the TMJs and the topographical distributions of these findings. In this investigation both joints of 22 edentulous individuals between 58 and 95 years of age were studied. Correlations were found between the right and left joints with respect to the anatomical location of the pathological findings.
Vertical to surface transmission electrophotonic device with selectable output light channels
Authors: Tashiro Y. , Hamao N. , Sugimoto M. , Takado N. , Asada S. , Kasahara K. , Yanase T.
Published: July 2002

A photoeletronic bistable device with selectable light output channels has been fabricated for implementation in photonic switching and processing systems. The device is a variation of the vertical to surface transmission electrophotonic device. Output in the stimulated light emission mode was successfully obtained from different waveguide channels by external electronic switching. Output channels could be switched at a rate of 400 Mb/s. The potential versatility of this device has been experimentally confirmed in programmable or switchable optical interconnections.
InGaAs/InP quantum well lasers with sub-mA threshold current
Authors: Temkin H. , Dutta N. K. , Tanbun-Ek T. , Logan R. A. , Sergent A. M.
Published: July 2002

We evaluate the effect of high-reflectivity facet coatings on the threshold current of lattice matched and compressively strained InGaAs/InP quantum well lasers. A large decrease in the threshold current is observed in structures with low internal losses. Coated lasers exhibit threshold currents as low as 1.1 mA at 20 °C and 0.9 mA at 10 °C, down from ∼15 mA in as-cleaved devices with cavity length of 200 μm. These changes are carefully modeled and the prospects for further reduction of the threshold current discussed.
Silicon epitaxy at 230 °C by reactive dc magnetron sputtering and its in situ ellipsometry monitoring
Authors: Feng G. F. , Katiyar M. , Maley N. , Abelson J. R.
Published: July 2002

We report epitaxial growth of silicon on Si(100) at 230 °C by reactive dc magnetron sputter deposition. Growth is monitored with in situ multiwavelength ellipsometry to determine the film microstructure. Film crystallinity depends on the partial pressure of hydrogen during deposition, and the best film is obtained with 2 mTorr H2. The films are found to have a bulk density deficit of a few percent and a low-density layer at the film-substrate interface. The microstructure is confirmed by transmission electron microscopy measurements. Infrared absorption and thermal hydrogen evolution measurements indicate that a large amount of molecular hydrogen is present at the substrate interface. We discuss the possible roles of hydrogen and particle bombardment in promoting epitaxial growth.
Blue and green diode lasers in ZnSe-based quantum wells
Authors: Jeon H. , Ding J. , Nurmikko A. V. , Xie W. , Grillo D. C. , Kobayashi M. , Gunshor R. L. , Hua G. C. , Otsuka N.
Published: July 2002

Laser diode operation has been obtained from (Zn,Cd)Se/ZnSe and (Zn,Cd)Se/Zn(S,Se) quantum well structures in the blue and the green. The devices, prepared on p- and n-type (In,Ga)As or GaAs buffer layers for lattice matching purposes to control the defect density, have been operated at near-room-temperature conditions and briefly at room temperature with uncoated end facets. Quasi-continuous wave operation has been obtained at T=77 K.
Low-threshold InGaAs strained-layer quantum-well lasers (λ=0.98 μm) with GaInP cladding layers and mass-transported buried heterostructure
Authors: Liau Z. L. , Palmateer S. C. , Groves S. H. , Walpole J. N. , Missaggia L. J.
Published: July 2002

Buried-heterostructure quantum-well lasers fabricated by mass transport are reported for In0.18Ga0.82As/GaAs/Ga0.5In0.5P strained-layer structures grown by atmospheric pressure organometallic vapor-phase epitaxy. Threshold current densities as low as 85 A/cm2 are measured for broad-stripe lasers, and buried-stripe devices show threshold currents as low as 3 mA and differential quantum efficiencies as high as 34% per facet without coatings.
(305) SrTiO3 as substrate for coherently tilted epitaxial YBa2Cu3Ox thin films
Authors: Aarnink W. A. M. , Reuvekamp E. M. C. M. , Verhoeven M. A. J. , Pedyash M. V. , Gerritsma G. J. , van Silfhout A. , Rogalla H. , Ryan T. W.
Published: July 2002

High Tc superconducting YBa2Cu3Ox (YBCO) thin films have been prepared on (305) SrTiO3 (STO) substrates. X-ray diffraction analysis and Rutherford backscattering experiments reveal that the c-axis of the layers is directed along the [001] STO axis. Bragg reflection measurements from YBCO lattice planes with high h, k, and l indices confirm that the film growth is epitaxial and almost single domain. For the critical current density jc(77 K) values of 2×106 and 1×103 A/cm2 have been found in the [010] and [501̄] YBCO directions, respectively.
Realization of an in-plane-gate single-electron transistor
Authors: Pothier H. , Weis J. , Haug R. J. , Klitzing K. v. , Ploog K.
Published: July 2002

By etching narrow trenches in an AlGaAs/GaAs heterostructure and defining a channel and six in-plane gates in the two-dimensional electron gas, a single-electron transistor is produced in a simple way. As expected from charging effects, the conductivity of the transistor oscillates with the voltage on each gate. However, in contrast to metallic devices or heterostructure devices with metallic top gates, the voltage dependent depletion of the gates themselves leads to changes in the period of the oscillations.
Diffraction from optically written persistent plasma gratings in doped compound semiconductors
Authors: Linke Richard A. , Thio Tineke , Chadi James D. , Devlin George E.
Published: July 2002

We propose and demonstrate a new type of optical nonlinearity based on the properties of the DX center in doped compound semiconductors. We report measurements on samples of AlGaAs:Si which were exposed to interfering laser beams and find diffraction from a large, persistent refractive index change associated with the well-known persistent photoconductivity effect in this material. The new effect is shown to exhibit a refractive index change 30 times larger than that of conventional photorefractive materials. We explain the origin of the refractive index change in terms of the plasma effect and show that its expected magnitude is consistent with our observations.
Thermal cycling apparatus for thermomechanical fatigue testing
Authors: Lawson Lawrence R.
Published: July 2002

A thermal cycling apparatus for fatigue testing is described. The sample is indirectly heated and cooled in order to allow direct observation and eliminate surface-to-bulk temperature gradients. Short-time constant heaters and coolers are described along with a method of waveform generation which takes the system’s thermal response into account.
Observation of a nanocrystalline-to-amorphous phase transition in luminescent porous silicon
Authors: Kunz R. R. , Nitishin P. M. , Clark H. R. , Rothschild M. , Ahern B.
Published: July 2002

Nanocrystalline silicon aggregates imbedded in a predominantly amorphous silicon layer have been observed in anodically etched p-Si(100) by using valence band x-ray photoelectron spectroscopy and lattice imaged high-resolution transmission electron microscopy (XTEM). XTEM has identified the as-prepared porous silicon to be a mixed phase of amorphous and nanocrystalline silicon, with the nanocrystalline aggregates being randomly dispersed throughout the full thickness of a 1 μm thick amorphous layer and exhibiting a size distribution from 2 to 5 nm in diameter. The abundance of the nanocrystalline aggregates seems to decrease as the anodic etching proceeds and as the sample is irradiated by x rays at room temperature in ultrahigh vacuum. Valence band photoelectron measurements show evidence for a crystalline-to-amorphous phase transition induced by x radiation which may, in part, be activated by photoelectron stimulated hydrogen desorption. The x-ray irradiated samples also exhibit a significant reduction in photoluminescence yield, possibly caused by a reduction in the density of nanocrystallites. The observed mixed phase porous silicon and the metastability of the nanocrystallites help to explain apparent contradictory descriptions of the nature of porous silicon.
Measurement of gated field emitter failures
Authors: Gilmore M. , McGruer N. E. , Browning J. , Bintz W. J.
Published: July 2002

The emerging field of vacuum microelectronics has many promising applications including flat-panel displays, microwave devices, and ionization sources. The technology is based on arrays of microfabricated micrometer-scaled gated field emitters. Applications are currently limited by unacceptable reliability due primarily to failures of individual field emitters. The failure of an individual emitter produces a characteristic electrical pulse. A circuit is used to monitor and count these pulses. The technique provides a powerful tool for exploration of stable operating regimes for vacuum microelectronic devices and may be useful in other areas in which vacuum discharges must be monitored.
Interpretation of capillary generated spatial and angular distributions of x rays: Theoretical modeling and experimental verification using the European Synchrotron Radiation Facility Optical beam line
Authors: Vincze L. , Janssens K. , Adams F. , Rindby A. , Engström P.
Published: July 2002

Using a detailed ray-tracing code for capillary optics, interpretation is given for parallel bore hole and tapered capillary generated far-field images. These images can be used to indicate the presence of various types of surface imperfections (i.e., surface roughness or waviness) or shape distortions of the optical device. The capillary output patterns were recorded at the optical beam line of the European Synchrotron Radiation Facility by using a monochromatic, highly parallel incident synchrotron beam. Capillaries of various dimensions were studied, with inlet diameters in the range of 30–70 μm, outlet diameters of 22–42 μm, and capillary length values ranging from 10 to 23 cm. The far-field images were taken at a distance of 10–11 cm from the capillary exit using a high resolution charge coupled device camera. By comparisons of simulated and experimental capillary output patterns, the effects of surface roughness/waviness, as well as axial distortions are studied with respect to the angular distribution of the generated capillary beam.
Direct SiO2/β-SiC(100)3×2 interface formation from 25 °C to 500 °C
Authors: Semond F. , Douillard L. , Soukiassian P. , Dunham D. , Amy F. , Rivillon S.
Published: July 2002

We investigate the β-SiC(100)3×2 surface oxidation by core level and valence band photoemission spectroscopies using synchrotron radiation. Low molecular O2 exposures on the (3×2) surface reconstruction leads to direct SiO2/β-SiC(100)3×2 interface formation already at room temperature (RT). To our best knowledge, this is the first example of RT oxidation leading directly to dominant silicon dioxide growth by O2 chemisorption only. The amount of SiO2 is enhanced when the surface temperature is raised by few hundred degrees only (<500 °C) during O2 exposures leading to ‘‘bulk oxide’’ formation already at small thicknesses. These findings are also relevant in low-temperature semiconductor oxide processing.
Effect of low temperature postannealing on the hole density of C δ-doped GaAs and Al0.3Ga0.7As
Authors: Li G. , Jagadish C.
Published: July 2002

In C δ-doped GaAs and Al0.3Ga0.7As grown by metalorganic vapor phase epitaxy using trimethylaluminium as a doping precursor, 20%–50% of the C acceptors are not electrically active due to hydrogen passivation. These hydrogen passivated C acceptors can be activated by low temperature postannealing in the N2 ambient. The amount of activated C acceptors depends on the postannealing temperature and postannealing time. After ∼10 min postannealing at 530 °C, most of hydrogen passivated C acceptors are activated, leading to a constant hole density with a further increase in postannealing time. At a given postannealing time of 15 min, an increased temperature always activates more hydrogen passivated C acceptors. There is no measurable change in the hole density after 15 min postannealing at temperatures below 450 °C. The activated C acceptors can be re-passivated by heating the postannealed C δ-doped (Al,Ga)As to 480 °C in the AsH3/H2 ambient but not in the H2 ambient. The as-grown C δ-doped GaAs with much less hydrogen passivation can be grown using the H2 cooling ambient.
Degradation mechanism of the AlInAs/GaInAs high electron mobility transistor due to fluorine incorporation
Authors: Hayafuji N. , Yamamoto Y. , Ishida T. , Sato K.
Published: July 2002

The electrical degradation of AlInAs/GaInAs high electron mobility transistor (HEMT) due to the fluorine contamination is quantitatively explained through the comprehensive annealing experiments and bias-temperature tests. The thermal degradation rate is found to be mainly determined by the following electrochemical reaction of fluorine with donor species after the quite fast diffusion of fluorine into the AlInAs layer. It is also confirmed that the thermal degradation is stringently affected by the electric field resulting in the one-sided degradation near the anode. These findings are valuable knowledges in improving the reliability of AlInAs/GaInAs HEMT under the dc accelerated life test at high temperature.
Precise control of island formation using overgrowth technique on cleaved edges of strained multiple quantum wells
Authors: Arai J. , Usami N. , Ota K. , Shiraki Y. , Ohga A. , Hattori T.
Published: July 2002

We propose an approach to control the position and the size of semiconductor islands formed by the Stranski–Krastanov growth mode. The method is to perform overgrowth on a cleaved edge of strained multiple quantum wells (SMQW), which give periodically modulated strain to the epitaxial layer. Proper choice of the growth conditions results in the formation of islands selectively on one of the constituents of the SMQW. The usefulness of this method was demonstrated by overgrowing Ge islands on the cleaved edges of Si0.8Ge0.2/Si SMQW. The Ge islands were selectively formed on the Si layer at 500 °C and on the Si0.8Ge0.2 layer at 600 °C. The former reflects the smaller critical thickness of Ge on Si, and the latter is driven by the minimization of strain energy owing to the smaller lattice mismatch between Ge and Si0.8Ge0.2.
Focused ion beam nanolithography on AlF3 at a 10 nm scale
Authors: Gierak J. , Vieu C. , Launois H. , Assayag G. Ben , Septier A.
Published: July 2002

We have investigated the potential use of AlF3 thin films (50 nm thick) as negative inorganic resist layers for focused ion beam nanolithography. We demonstrate that 10 nm-wide lines can be fabricated using a Ga+ beam of 30 keV incident energy. The resist sensitivity of 1010 Ga+/cm is two orders of magnitude lower than for polymethylmethacrylate organic resist. We emphasize that this low sensitivity associated with the exposure mechanism of the resist minimize the influence of the tails of the current distribution within the ion spot.
Growth and characterization of InAs/GaSb photoconductors for long wavelength infrared range
Authors: Mohseni H. , Michel E. , Sandoen Jan , Razeghi M. , Mitchel W. , Brown G.
Published: July 2002

In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 μm and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of 1.33×109 cm Hz1/2/W at 10.3 μm at 78 K.
Thin films of aluminum nitride and aluminum gallium nitride for cold cathode applications
Authors: Sowers A. T. , Christman J. A. , Bremser M. D. , Ward B. L. , Davis R. F. , Nemanich R. J.
Published: July 2002

Cold cathode structures have been fabricated using AlN and graded AlGaN structures (deposited on n-type 6H-SiC) as the thin film emitting layer. The cathodes consist of an aluminum grid layer separated from the nitride layer by a SiO2 layer and etched to form arrays of either 1, 3, or 5 μm holes through which the emitting nitride surface is exposed. After fabrication, a hydrogen plasma exposure was employed to activate the cathodes. Cathode devices with 5 μm holes displayed emission for up to 30 min before failing. Maximum emission currents ranged from 10–100 nA and required grid voltages ranging from 20–110 V. The grid currents were typically 1 to 104 times the collector currents.
Photostimulable luminescence and imaging in vapor-deposited BaFCl:Eu thin film phosphors
Authors: Carcia P. F. , McLean R. S. , Crawford M. K. , Jones B. D.
Published: July 2002

Thin films of BaFCl:Eu with photostimulable luminescence (PSL) were grown by vapor deposition. For substrate temperatures at or below 350 °C, films were optically transparent and exhibited higher resolution in x-ray imaging than a commercial, particulate PSL phosphor screen, when luminescence was stimulated by scanning with a focused HeNe laser. Although post annealing films in a hydrogen atmosphere at 600–900 °C increased their PSL signal, which was relatively weak in as-deposited films, annealing reduced imaging resolution, apparently because of an increase in optical scattering of the focused laser. The implications of hydrogen annealing for the PSL mechanism are also discussed.
Probing structure and magnetism of CoNi/Pt interfaces by nonlinear magneto-optics
Authors: Kirilyuk A. , Rasing Th. , Haast M. A. M. , Lodder J. C.
Published: July 2002

Magnetic CoNi/Pt interfaces are studied as a function of their preparation conditions by magnetization-induced second-harmonic generation (MSHG) measurements. A detailed method has been developed to decompose the total MSHG response into magnetic and crystallographic contributions for each interface. Although the bulk magnetism of the CoNi film (3 nm thick) shows only a subtle dependence on the sputtering Ar pressure, the interfaces appear to be dramatically affected. It can be shown that the crystallographic part probes the increase in the interface roughness while the magnetic one clearly reveals a maximum in the in-plane magnetization of the interface.
Effect of Ti substitution on the thermoelectric properties of the pentatelluride materials M1−xTixTe5 (M=Hf, Zr)
Authors: Littleton R. T. , Tritt Terry M. , Feger C. R. , Kolis J. , Wilson M. L. , Marone M. , Payne J. , Verebeli D. , Levy F.
Published: July 2002

The thermoelectric properties (resistivity and thermopower) of single crystals of the low dimensional pentatelluride materials, HfTe5  and ZrTe5, have been measured as a function of temperature from 10 K<T<320 K. The effect of small amounts of Ti substitutional doping (M1−xTixTe5, where M=Hf, Zr) on the thermoelectric properties is reported here. A resistive transition occurs in the pentatellurides, as evidenced by a peak in the resistivity, TP≈80 K for HfTe5 and TP≈145 K for ZrTe5. Both parent materials exhibit a large positive (p-type) thermopower near room temperature which undergoes a change to negative (n-type) below the peak temperature. The thermal conductivity is relatively low (≈5 W/m K) for the MTe5 materials. The Ti substitution affects the electronic properties strongly, producing a substantial shift in the peak temperature while the large values of thermopower remain essentially unaffected. These results warrant further investigation of these materials as candidates for low temperature thermoelectric applications.
Determination of the optical constants of zinc oxide thin films by spectroscopic ellipsometry
Authors: Washington P. L. , Ong H. C. , Dai J. Y. , Chang R. P. H.
Published: July 2002

Spectroscopic ellipsometry (SE) has been used to determine the complex pseudo dielectric functions, ε1(E)+iε2(E), of ZnO films on (0001) Al2O3 substrates over the spectral range of 1.33 and 4.96 eV at room temperature. The SE measurements are carried out with E⊥c at angles of incidence of 60° and 65° with respect to the surface normal. Below the band gap, the refractive index n is found to follow the first order Sellmeir dispersion relationship n2(λ)=1+1.881λ2/(λ2−0.05382). A free excitonic structure located at the band edge of 3.32 eV is clearly observed in the pseudo absorption spectrum. Elliott expression with Lorentzian broadening is used to model the pseudo absorption coefficient above the band edge.
Lattice location of Si in ion implanted GaN
Authors: Kobayashi H. , Gibson W. M.
Published: July 2002

The lattice location of Si in GaN has been investigated by ion channeling in combination with Rutherford backscattering spectrometry, particle induced x-ray emission, and nuclear reaction analysis. Metalorganic chemical vapor deposition grown GaN on c-plane sapphire substrates and implanted with Si28 at a dose of 7×1014 cm−2 with postimplant annealing were investigated. It was found that almost 100% of Si goes into the Ga site at 1100 °C. Our results directly indicate that the electrical activation of Si implanted GaN with postimplant annealing is due to the formation of substitutional Si at this temperature.
Self-patterning nano-electrodes on ferroelectric thin films for gigabit memory applications
Authors: Alexe M. , Scott J. F. , Curran C. , Zakharov N. D. , Hesse D. , Pignolet A.
Published: July 2002

In the present work, we report self-assembling bismuth-containing nano-electroded cells of layered perovskite ferroelectric thin films that are about 200 nm in size, that is 50 times smaller than the smallest cell reported to date. Heteroepitaxial Bi-rich Bi4Ti3O12 films were grown by pulsed laser deposition (PLD) on top of epitaxial conductive La0.5Sr0.5CoO3 (LSCO) layers equally deposited by PLD. The epitaxial LSCO has been grown on top of an epitaxial CeO2 yttrium-stabilized zirconia (YSZ) stack, itself deposited by PLD on Si(100) substrates. As a consequence of the high substrate temperature during the epitaxial deposition of the Bi4Ti3O12 layer, the excess Bi segregates, migrates to the surface where it forms a self-organized array of epitaxial mesas which possess metallic-like electrical characteristics.
Vertical device architecture by molding of organic-based thin film transistor
Authors: Garnier Francis , Hajlaoui Riadh , El Kassmi Mohamed
Published: July 2002

An organic thin film transistor (TFT) of circular geometry is constructed by the use of polymer-based substrate, insulator, and semiconductor. Owing to the plasticity of organic materials, this device is mechanically molded by pressing the central circular drain electrode. A shallow well is created, resulting in the localization of the transistor channel onto the wall of the well. The electrical characteristics of the transistor remain almost unchanged after this molding. The obtained vertical device architecture allows the use of a very large channel width over length ratio, while preserving a maximum drain electrode area to be devoted to the further deposition of liquid crystal or an electroluminescent film. Current output of the order of some milliamperes per square centimeter can be delivered, which makes these molded TFTs well adapted for the construction of display pixels.
Shape transition of InAs quantum dots by growth at high temperature
Authors: Saito Hideaki , Nishi Kenichi , Sugou Shigeo
Published: July 2002

The shape of InAs quantum dots grown on GaAs substrates by molecular beam epitaxy is investigated at various growth temperatures. A dot with a new shape surrounded by {110} facets and having a high aspect ratio appears at temperatures over 510 °C. This dot is transformed from a pyramid shape (low aspect ratio) when its volume exceeds a critical value by raising the growth temperature. The shape transition indicates that the high-aspect-ratio dot is energetically favorable at a large volume. A narrow energy width of photoluminescence, 35 meV at room temperature, is obtained by the growth of the high-aspect-ratio dots, which have a fairly good size uniformity of less than 4% deviation.
Room-temperature visible and infrared photoluminescence from Pr-implanted GaN films by focused-ion-beam direct write
Authors: Chao L. C. , Steckl A. J.
Published: July 2002

Visible and infrared photoluminescence (PL) have been obtained from Pr-implanted GaN films using focused-ion-beam (FIB) direct write utilizing a Pr–Pt liquid alloy ion source. FIB implantation was performed on GaN films grown by molecular-beam epitaxy (MBE), hydride vapor-phase epitaxy, and metalorganic chemical-vapor deposition. After annealing, strong room-temperature emission was observed in the red (at 650 nm) and in the infrared (at several wavelengths including 0.96, 1.3, and 1.9 μm). Essentially identical PL spectra were obtained in the implanted GaN films as in the in situ Pr-doped GaN films grown by MBE.
Fluorescence scanning near-field optical microscopy of conjugated polymer blends
Authors: Stevenson R. , Granström M. , Richards D.
Published: July 2002

Fluorescence scanning near-field optical microscopy with a spatial resolution of ∼150 nm is used to investigate blends of conjugated polymers in a poly(methylmethacrylate), PMMA, matrix. These blends, which phase segregate on a length scale of several hundred nanometers, have a high degree of correlation between their fluorescence and topographic images, as illustrated by measurements taken from a sample of 5% by weight of poly(2-methoxy-5-(2′,6′-dimethyloctyloxy)-pphenylenevinylene), “OC1C10” PPV, in PMMA. In a blend containing both poly(2,5-dihexyloxyp-phenylenevinylene), CN-PPV, and poly(2-dimethyloctylsilyl-p-phenylenevinylene), DMOS-PPV, spectroscopic contrast was used to identify material both on the surface and buried within a thin transparent film.
Effect of channel doping on the low-frequency noise in GaN/AlGaN heterostructure field-effect transistors
Authors: Balandin A. , Morozov S. , Wijeratne G. , Cai S. J. , Li R. , Li J. , Wang K. L. , Viswanathan C. R. , Dubrovskii Yu.
Published: July 2002

We examined low-frequency noise in doped and undoped channel GaN/AlGaN/SiC heterostructure field-effect transistors with different Al content in the barrier. The observed noise spectra follow the 1/fγ law with 0.8⩽γ⩽1.2 for frequencies f up to 100 kHz. Our results indicate two orders of magnitude reduction in the input-referred noise spectral density in the undoped channel devices with respect to the noise density in the doped channel devices of comparable electric characteristics. Low temperature measurements reveal generation—recombination-type peaks in the spectra of the doped channel devices. Effects of the piezoelectric charges at the GaN/AlGaN interface are also discussed.
Single-wall carbon nanotube circuits assembled with an atomic force microscope
Authors: Lefebvre J. , Lynch J. F. , Llaguno M. , Radosavljevic M. , Johnson A. T.
Published: July 2002

We have developed a method to assemble single-wall carbon nanotube (SWNT) circuits using a tapping mode atomic force microscope. Nanotubes can be controllably translated, rotated, cut, and placed on top of one another by varying the tip–sample force, and the tip speed. These operations let us construct complex nanotube circuits, which are contacted using electron beam lithography. We present data from a circuit of two crossed SWNT bundles. The lower bundle behaves as two quantum dots in series, separated by a tunnel barrier created at the junction. Gate voltages can tune the number of charges on each dot and the tunnel barrier transmission.
Optical characterization of the self-limiting effect in flow-rate modulation epitaxy of V-shaped GaAs quantum wire
Authors: Wang Xue-Lun , Mutsuo Ogura
Published: July 2002

Photoluminescence is used to characterize the self-limiting effect observed during flow-rate modulation epitaxy (FME) of GaAs quantum wires (QWRs) on V-grooved substrate. Our study found that not only the central thickness but also the overall cross-sectional wire shape is maintained to an atomic level in the self-limited growth regions. This result suggests that the self-limited FME technique is a very promising method for an atomically controlled fabrication of high-quality QWRs.
Size-dependent electron-hole exchange interaction in Si nanocrystals
Authors: Brongersma M. L. , Kik P. G. , Polman A. , Min K. S. , Atwater Harry A.
Published: July 2002

Silicon nanocrystals with diameters ranging from ≈2 to 5.5 nm were formed by Si ion implantation into SiO2 followed by annealing. After passivation with deuterium, the photoluminescence (PL) spectrum at 12 K peaks at 1.60 eV and has a full width at half maximum of 0.28 eV. The emission is attributed to the recombination of quantum-confined excitons in the nanocrystals. The temperature dependence of the PL intensity and decay rate at several energies between 1.4 and 1.9 eV was determined between 12 and 300 K. The temperature dependence of the radiative decay rate was determined, and is in good agreement with a model that takes into account the energy splitting between the excitonic singlet and triplet levels due to the electron-hole exchange interaction. The exchange energy splitting increases from 8.4 meV for large nanocrystals (≈5.5 nm) to 16.5 meV for small nanocrystals (≈2 nm). For all nanocrystal sizes, the radiative rate from the singlet state is 300–800 times larger than the radiative rate from the triplet state.
Annealing dynamics of nitrogen-implanted GaAs films investigated by current–voltage and deep-level transient spectroscopy
Authors: Chen J. F. , Wang J. S. , Huang M. M. , Chen N. C.
Published: July 2002

We present electrical data to show that, after nitrogen implantation, GaAs films become resistive after high-temperature annealing. The activation energies of the resistance are determined to be 0.34, 0.59, and 0.71 eV after annealing at 500, 700, and 950 °C, respectively. The increase in the activation energy with increasing annealing temperature can be explained by the results of traps detected in deep-level transient spectroscopy, where two traps at 0.32 and 0.70 eV are observed in the samples after annealing. The intensity of the trap at 0.32 eV is found to reduce by annealing. By comparing to the result of the x-ray diffraction, we suspect that this trap is related to the lattice-expansion defects. The trap at 0.70 eV is observed only in samples annealed at high temperatures. Since this trap contributes to the high-resistive effect, we believe that it is associated with the nitrogen ions.