Search query: semiconductor nanomaterials models

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abstract: Abstract The modelling and simulation of low dimensional nanoelectronic devices is important, because the semiconductor industry has scaled transistors down to the sub 10 n m regime. The top of the barrier (ToB) transistor model has been developed and used to model transistors that are composed of various semiconducting materials. In this paper, a brief overview of the ToB transistor model is presented. The main objective of this paper is to provide a focused review on the device modelling milestones that have been achieved using the ToB transistor model. The accuracy of a few of these models is assessed by computing the normalised root mean square deviation. The ToB transistor model is widely used for computational studies on low dimensional field effect transistors with various channel materials, such as ultra thin bodies, two dimensional materials and one dimensional materials. The ToB transistor model is also useful for extensive research in circuit level simulations. In summary, this nanoscale model helps researchers to identify and evaluate the potential nanomaterials for future nanoelectronic applications.
author_names: Mu Wen Chuan

Kien Liong Wong

Afiq Hamzah

Shahrizal Rusli

Nurul Ezaila Alias

Cheng Siong Lim

Michael L P Tan
title: A review of the top of the barrier nanotransistor models for semiconductor nanomaterials
year: 2020

abstract: In this study, we will compare the study done by different researchers on the semiconductor II VI group material by using different models including DMR (Diffusivity Mobility Ratio) We will check out the DMR and other model parameters used to compare the performance of semiconductor II VI group material. The basic formulation and the study of these models will help us to understand the basic properties of the nanomaterials studied so far. Keywords: DMR, Einstein relation, models, nanomaterial, semiconductor material group II VI
author_names: Rahul Jain

Kh Gopal Krishna Singh
title: Comparative study of models for II VI group semiconductor nanomaterials using DMR
year: 2018

abstract: As synthesized colloidal indium nitride (InN) nanocrystals are degenerately doped with carrier densities large enough to lead to strong localized surface plasmon resonances (LSPR) in the infrared. Intriguingly, the LSPR energy is almost independent of carrier density, which premises that simple classical models that are often used to describe metallic systems inadequately describe the plasmonic response of InN nanoparticles. Here, an oxidative titration approach is used to directly quantify carrier densities in colloidal InN nanocrystals, eliminating the need to rely on any specific model. A size independent carrier density value of (7.4 0.4) x 1020 cm 3 is obtained for diameters varying between 4 and 9 nm, corresponding to about 30 to 300 electrons per nanocrystal, depending on size. Upon oxidation with nitrosonium salts, the carrier density in InN nanocrystals can be reduced to (3.9 0.3) x 1020 cm 3, also independent of size. The unusual plasmonic signatures of colloidal InN nanocrystals are shown t.
author_names: Zhihui Liu

Remi Beaulac
title: Nature of the Infrared Transition of Colloidal Indium Nitride Nanocrystals: Nonparabolicity Effects on the Plasmonic Behavior of Doped Semiconductor Nanomaterials
year: 2017

abstract: Nanotechnology and engineered nanomaterials (ENM) empower existing technologies. One of the great examples are III V semiconductor nanowires (NW) which have a broad application range. The occupational safety and hazard organizations draw attention to ENM, as their physical and chemical characteristics differ from the ones of bulk materials. Additionally, the NW high aspect ratio geometry is of great concern, since it resembles the morphology of asbestos. Moreover, due to their small size, ENM materials are hard to detect and identify using conventional methods. During ENM technology development and large scale production, the highest risk of human exposure is via inhalation. Therefore, we need to study how NW affect lung tissue using experimental exposure models. The work in this thesis aimed at filling the knowledge gap in ENM detection and identification, as well as understanding III V semiconductor NW effects in in vitro and in vitro models.We have used enhanced darkfield microscopy hyperspectral imaging method to detect and identify ceria nanoparticles in three differently prepared samples, and compared different combinations of data analysis methods. The remaining part of the thesis was devoted to the study of the III V semiconductor NW effects on cells and tissue in vitro and in vivo. We have exposed two types of cell cultures (primary human lung (SAE) and human lung adenocarcinoma cell line (A549) to gallium phosphide (GaP) NW. We observed that both type of cells are capable to engulf NW after 2 days, and that NW do not have any effect on the SAE and A549 cell morphology after 7 and 5 days, respectively. The NW concentrations used in this work are not toxic to A549 cells, since we did not see a change in cell mobility, viability or changes in ROS levels. After inhibiting specific endocytosis pathways in A549 cells, we showed that NW are actively taken up via phagocytosis and/or macropinocytosis.Additionally, we have performed in vivo mice exposure to GaP NW via intratracheal instillation. We have observed that NW induce an inflammation and allergic reaction of similar levels as the ones observed after exposure to carcinogenic multiwall carbon nanotubes. Additionally, we show that NW are capable to cross tissue barriers and reach distant organs after 28 days, however without introducing changes to the organ tissues. Lastly, we have performed a pilot study, where we investigated the effect of NW photodiodes on A549 cells. We observed that the presence of light inhibits cell proliferation. Furthermore, we show that the chemical make up of the photodiodes is important, since some photodiodes dissolve in water based cell culturing media and release toxic compounds. (Less)
author_names: Laura Abariute
title: Engineered nanomaterials in in vivo and in vitro models
year: 2018

abstract: In designing and optimizing new generation nanomaterials and related quantum devices, dissipation versus decoherence phenomena are often accounted for via local scattering models, such as relaxation time and Boltzmann like schemes. Here we show that the use of such local scattering approaches within the Wigner function formalism may lead to unphysical results, namely anomalous suppression of intersubband relaxation, incorrect thermalization dynamics, and violation of probability density positivity. Furthermore, we propose a quantum mechanical generalization of relaxation time and Boltzmann like models, resulting in nonlocal scattering superoperators that enable one to overcome such limitations.
author_names: Rita Claudia Iotti

Fabrizio Dolcini

Fausto Rossi
title: Wigner function formalism applied to semiconductor quantum devices: Need for nonlocal scattering models
year: 2017

abstract: Rationale: Despite growing use of engineered nanomaterials (ENM) in applications from electronics to medicine, the potential risk to human health remains a critical concern within clinical use. ENM exposure during pregnancy can potentially cause reproductive toxicity even at levels that produce no measurable harm to animals in normal conditions. Methods: Phospholipid micelle encapsulated CdSe/CdS/ZnS semiconductor nanocrystals with an average hydrodynamic diameter of 60 nm were intravenously injected during pregnancy in both rodent and nonhuman primate animal models. Cadmium concentration levels and maternal haematological and biochemical markers were determined, along with histopathological examination of major organs. Results: Nanocrystals were found to have crossed the placenta from mother to fetus in both rodents and nonhuman primates. However, the animal models display different responses with respect to reproductive toxicity. In the rodent model, toxicity symptoms are absent in treated subjects, with no observed gestational or fetal abnormalities and complications. A significantly higher miscarriage rate of 60% is recorded for macaques after prenatal nanoparticle administration. There was a miscarriage rate of 15% in the general population despite only ~0.16% of the initial cadmium dose present in the fetus. Blood and biochemical markers of treated macaques indicate acute hepatocellular injury within a week after nanoparticle administration. Histology of major organs of the miscarried macaque fetuses show no abnormalities. Conclusion: The potential of nanomaterials to cross the placenta and impact fetal survival in primates suggest the necessity of precautionary measures to prevent gestational exposure of ENMs.
author_names: Ling Ye

Rui Hu

Liwei Liu

Jianwei Liu

Jing Liu

Hongyan Chen

Ya-zhuo Hu

Ya-qian Liu

Xin Liu

Cui Liu

Danny Jian Hang Tng

Yuanguang Meng

Junle Qu

Mark T Swihart

Ken-Tye Yong
title: Comparing Semiconductor Nanocrystal Toxicity in Pregnant Mice and Non Human Primates
venue: Nanotheranostics
year: 2019

abstract: This paper presents a methodology to quantify oxidizing and reducing gases using n type and p type chemiresistive sensors, respectively. Low temperature sensor heating with pulsed UV or visible light modulation is used together with the application of the fast Fourier transform (FFT) to extract sensor response features. These features are further processed via principal component analysis (PCA) and principal component regression (PCR) for achieving gas discrimination and building concentration prediction models with R2 values up to 98% and RMSE values as low as 5% for the total gas concentration range studied. UV and visible light were used to study the influence of the light wavelength in the prediction model performance. We demonstrate that n type and p type sensors need to be used together for achieving good quantification of oxidizing and reducing species, respectively, since the semiconductor type defines the prediction model's effectiveness towards an oxidizing or reducing gas. The presented method reduces considerably the total time needed to quantify the gas concentration compared with the results obtained in a previous work. The use of visible light LEDs for performing pulsed light modulation enhances system performance and considerably reduces cost in comparison to previously reported UV light based approaches.
author_names: Ernesto Gonzalez

Juan Casanova-Chafer

Aanchal Alagh

Alfonso Romero

Xavier Vilanova

Selene Acosta

Damien Cossement

Carla Bittencourt

Eduard Llobet
title: On the Use of Pulsed UV or Visible Light Activated Gas Sensing of Reducing and Oxidising Species with WO3 and WS2 Nanomaterials
venue: Sensors
year: 2021

abstract: Abstract Zn 1 x Er x O polycrystalline nanoparticles with various compositions x 0.01 0.02 0.03 0.04 0.05 and 0.10 were prepared using sol gel techniques, for which zinc acetate dihydrate and erbium 2 4 pentanedionate are used as precursors. Nanoparticles were pressed under a pressure of 4 tons for 5 min into disk shaped compacts with 2 mm thicknesses and 10 mm diameters. The pressed samples were annealed at 400 degC for 30 min. X ray diffraction (XRD) scanning electron microscopy (SEM) and Vickers microhardness analyses of the produced Er doped ZnO bulk nanomaterials were performed. Specifically, in this study we focused on the analysis of their mechanical properties. Undoped and Er doped bulk samples were investigated according to Meyer's law; the proportional sample resistance (PSR) elastic/plastic deformation (EPD) and indentation induced cracking (IIC) models; and the Hays Kendal (HK) approach. As a result, the IIC model was more suitable to determine the micromechanical properties and the reverse indentation size effect R ISE behavior of Er doped ZnO semiconductors.
author_names: Elif Asikuzun

O Ozturk
title: Comparison of theoretical and experimental microhardness of tetrahedral binary Zn1 xErxO semiconductor polycrystalline nanoparticles
venue: Ceramics International
year: 2019

abstract: In the last two decades, colloidal semiconductor nanocrystals have emerged as a phenomenal research topic due to their size dependent optoelectronic properties and to their outstanding versatility in many technological applications. In this review, we provide an historical account of the most relevant computational works that have been carried out to understand atomistically the electronic structure of these materials, including the main requirements needed for the preparation of nanocrystal models that align well with the experiments. We further discuss how the advancement of these computational tools has affected the analysis of these nanomaterials over the years. We focus our review on the three main families of colloidal semiconductor nanocrystals: group II VI and IV VI metal chalcogenides, group III V metal pnictogenides and metal halides, in particular lead based halide perovskites. We discuss the most recent research frontiers and outline the future outlooks expected in this field from a computational perspective.
author_names: R Pascazio

Juliette Zito

I Infante
title: An Overview of Computational Studies on Colloidal Semiconductor Nanocrystals.
venue: Chimia
year: 2021

abstract: On decreasing size down to nanoscale, the physical, optical and quantum mechanical properties of the materials no longer remain constant but become tuneable. In order to understand these unusual properties of nanomaterials, some theoretical models and experiments have been proposed from various perspectives. The explanation of energy band gap increment can be presented in terms of quantum confinement effect. A simple model based on cohesive and activation energy, free from adjustable parameters to calculate the size and shape dependent band gap expansion is derived for the semiconductor nanocompounds. The model predicts that the energy band gap increases on decreasing the size of the particle of nanomaterial semiconductors. Also, it is seen that the effects of shape alter the band gap energy of nanomaterials and this effect on band gap energy becomes larger with the decrease in particle size. Our predictions are very consistent with the available experimented data and the simulation results.
author_names: Madan Singh

Abhishek Singhal
title: Modeling of Shape and Size Effects for the Band Gap of Semiconductor Nanoparticles
venue: 2018 2nd International Conference on Micro Electronics and Telecommunication Engineering (ICMETE)
year: 2018