Moussab/ORKG-training-evaluation-set huggingface dataset:
Research field: Engineering
Title: RF MEMS Shunt Capacitive Switches Using AlN Compared to Si3N4 Dielectric
Abstract: RF microelectromechanical systems (MEMS) capacitive switches for two different dielectrics, aluminum nitride (AlN) and silicon nitride (Si3N4), are presented. The switches have been characterized and compared in terms of DC and RF performance (5-40 GHz). Switches based on AlN have higher down-state capacitance for similar dielectric thicknesses and provide better isolation and smaller insertion losses compared to Si3N4 switches. Experiments were carried out on RF MEMS switches with stiffening bars to prevent membrane deformation due to residual stress and with different spring and meander-type anchor designs. For a ~300-nm dielectric thickness, an air gap of 2.3 μm and identical spring-type designs, the AlN switches systematically show an improvement in the isolation by more than -12 dB (-35.8 dB versus -23.7 dB) and a better insertion loss (-0.68 dB versus -0.90 dB) at 40 GHz compared to Si3N4. DC measurements show small leakage current densities for both dielectrics (<;10-8 A/cm2 at 1 MV/cm). However, the resulting leakage current for AlN devices is ten times higher than for Si3N4 when applying a larger electric field. The fabricated switches were also stressed by applying different voltages in air and vacuum, and dielectric charging effects were investigated. AlN switches eliminate the residual or injected charge faster than the Si3N4 devices do.
Extracted statement — Real down-state capacitance - Cr (pF): 0.9
Research field: Engineering
Title: Efficiently Improving the Stability of Inverted Perovskite Solar Cells by Employing Polyethylenimine-Modified Carbon Nanotubes as Electrodes
Abstract: Inverted perovskite solar cells (PSCs) have been becoming more and more attractive, owing to their easy-fabrication and suppressed hysteresis, while the ion diffusion between metallic electrode and perovskite layer limit the long-term stability of devices. In this work, we employed a novel polyethylenimine (PEI) modified cross-stacked superaligned carbon nanotube (CSCNT) film in the inverted planar PSCs configurated FTO/NiO x/methylammonium lead tri-iodide (MAPbI3)/6, 6-phenyl C61-butyric acid methyl ester (PCBM)/CSCNT:PEI. By modifying CSCNT with a certain concentration of PEI (0.5 wt %), suitable energy level alignment and promoted interfacial charge transfer have been achieved, leading to a significant enhancement in the photovoltaic performance. As a result, a champion power conversion efficiency (PCE) of ∼11% was obtained with a Voc of 0.95 V, a Jsc of 18.7 mA cm-2, a FF of 0.61 as well as negligible hysteresis. Moreover, CSCNT:PEI based inverted PSCs show superior durability in comparison to the standard silver based devices, remaining over 85% of the initial PCE after 500 h aging under various conditions, including long-term air exposure, thermal, and humid treatment. This work opens up a new avenue of facile modified carbon electrodes for highly stable and hysteresis suppressed PSCs.
Extracted statement — Open circuit voltage, Voc (V): 0.95
Research field: Engineering
Title: Simplified Hollow-Core Fiber-Based Fabry–Perot Interferometer With Modified Vernier Effect for Highly Sensitive High-Temperature Measurement
Abstract: In this paper, a high-temperature fiber sensor based on an optical fiber Fabry-Perot interferometer is fabricated by splicing a section of simplified hollow-core fiber between two single-mode fibers (SMFs) and cleaving one of the two SMFs to a certain length. With the superposition of three beams of light reflected from two splicing joints and end face of the cleaved SMF, the modified Vernier effect will be generated in the proposed structure and improve the sensitivity of temperature measurement. The envelope of spectrum reflected from the proposed sensor head is modulated by the ambient temperature of the sensor head. By monitoring and measuring the shift of spectrum envelope, the measurement of environment temperature is carried out experimentally, and high temperature sensitivity of 1.019 nm/°C for the envelope of the reflected spectrum was obtained. A temperature measurement as high as 1050 °C has been achieved with excellent repeatability.
Extracted statement — Sensitivity (nm/°C): 1.019
Research field: Engineering
Title: Flexible capacitive pressure sensor with sensitivity and linear measuring range enhanced based on porous composite of carbon conductive paste and polydimethylsiloxane
Abstract: In recent years, the development of electronic skin and smart wearable body sensors has put forward high requirements for flexible pressure sensors with high sensitivity and large linear measuring range. However it turns out to be difficult to increase both of them simultaneously. In this paper, a flexible capacitive pressure sensor based on porous carbon conductive paste-PDMS composite is reported, the sensitivity and the linear measuring range of which were developed using multiple methods including adjusting the stiffness of the dielectric layer material, fabricating micro-structure and increasing dielectric permittivity of dielectric layer. The capacitive pressure sensor reported here has a relatively high sensitivity of 1.1 kPa-1 and a large linear measuring range of 10 kPa, making the product of the sensitivity and linear measuring range is 11, which is higher than that of the most reported capacitive pressure sensor to our best knowledge. The sensor has a detection of limit of 4 Pa, response time of 60 ms and great stability. Some potential applications of the sensor were demonstrated such as arterial pulse wave measuring and breathe measuring, which shows a promising candidate for wearable biomedical devices. In addition, a pressure sensor array based on the material was also fabricated and it could identify objects in the shape of different letters clearly, which shows a promising application in the future electronic skins.
Extracted statement — Sensibility of the pressure sensor ( /kPa): 1.1
Research field: Engineering
Title: Highly Sensitive, Transparent, and Durable Pressure Sensors Based on Sea-Urchin Shaped Metal Nanoparticles
Abstract: Highly sensitive, transparent, and durable pressure sensors are fabricated using sea-urchin-shaped metal nanoparticles and insulating polyurethane elastomer. The pressure sensors exhibit outstanding sensitivity (2.46 kPa-1 ), superior optical transmittance (84.8% at 550 nm), fast response/relaxation time (30 ms), and excellent operational durability. In addition, the pressure sensors successfully detect minute movements of human muscles.
Extracted statement — Sensitivity (/kPa): 2.46
Research field: Engineering
Title: Integration of piezoelectric aluminum nitride and ultrananocrystalline diamond films for implantable biomedical microelectromechanical devices
Abstract: The physics for integration of piezoelectric aluminum nitride (AlN) films with underlying insulating ultrananocrystalline diamond (UNCD), and electrically conductive grain boundary nitrogen-incorporated UNCD (N-UNCD) and boron-doped UNCD (B-UNCD) layers, as membranes for microelectromechanical system implantable drug delivery devices, has been investigated. AlN films deposited on platinum layers on as grown UNCD or N-UNCD layer (5–10 nm rms roughness) required thickness of ∼400 nm to induce (002) AlN orientation with piezoelectric d33 coefficient ∼1.91 pm/V at ∼10 V. Chemical mechanical polished B-UNCD films (0.2 nm rms roughness) substrates enabled (002) AlN film 200 nm thick, yielding d33 = 5.3 pm/V.
Extracted statement — Piezoelectric coefficient measured (pm/V): 5.3
Research field: Engineering
Title: Microstructure and Electrical Properties of Novel piezo-optrodes Based on Thin-Film Piezoelectric Aluminium Nitride for Sensing
Abstract: Thin-film piezoelectric materials are currently employed in micro- and nanodevices for energy harvesting and mechanical sensing. The deposition of these functional layers, however, is quite challenging onto non-rigid/non-flat substrates, such as optical fibers (OFs). Besides the recent novel applications of OFs as probes for biosensing and bioactuation, the possibility to combine them with piezoelectric thin films and metallic electrodes can pave the way for the employment of novel opto-electro-mechanical sensors (e.g., waveguides, optical phase modulators, tunable filters, energy harvesters or biosensors). In this work the deposition of a thin-film piezoelectric wurtzite-phase Aluminium Nitride (AlN), sandwiched between molybdenum (Mo) electrodes, on the curved lateral surface of an optical fiber with polymeric cladding, is reported for the first time, without the need of an orientation-promoting interlayer. The material surface properties and morphology are characterized by microscopy techniques. High orientation is demonstrated by SEM, PFM and X-ray diffraction analysis on a flat polymeric control, with a resulting piezoelectric coefficient (d33) of ∼5.4 pm/V, while the surface roughness Rms measured by AFM is 9 ÷ 16 nm. The output mechanical sensing capability of the resulting AlN-based piezo-optrode is investigated through mechanical buckling tests: the peak-to-peak voltage for weakly impulsive loads increases with increasing relative displacements (up to 30%), in the range of 20 ÷ 35 mV. Impedance spectroscopy frequency sweeps (10 kHz-1 MHz, 1 V) demonstrate a sensor capacitance of ∼8 pF, with an electrical Q factor as high as 150. The electrical response in the long-term period (two months) revealed good reliability and durability.
Extracted statement — Piezoelectric coefficient measured (pm/V): 5.4
Research field: Engineering
Title: Preparation of highly c-axis oriented AlN thin films on Hastelloy tapes with Y2O3 buffer layer for flexible SAW sensor applications
Abstract: Highly c-axis oriented aluminum nitrade (AlN) films were successfully deposited on flexible Hastelloy tapes by middle-frequency magnetron sputtering. The microstructure and piezoelectric properties of the AlN films were investigated. The results show that the AlN films deposited directly on the bare Hastelloy substrate have rough surface with root mean square (RMS) roughness of 32.43nm and its full width at half maximum (FWHM) of the AlN (0002) peak is 12.5∘. However, the AlN films deposited on the Hastelloy substrate with Y2O3 buffer layer show smooth surface with RMS roughness of 5.46nm and its FWHM of the AlN (0002) peak is only 3.7∘. The piezoelectric coefficient d33 of the AlN films deposited on the Y2O3/Hastelloy substrate is larger than three times that of the AlN films deposited on the bare Hastelloy substrate. The prepared highly c-axis oriented AlN films can be used to develop high-temperature flexible SAW sensors.
Extracted statement — Surface roughness (nm): 5.46
Research field: Engineering
Title: Low temperature aluminum nitride thin films for sensory applications
Abstract: A low-temperature sputter deposition process for the synthesis of aluminum nitride (AlN) thin films that is attractive for applications with a limited temperature budget is presented. Influence of the reactive gas concentration, plasma treatment of the nucleation surface and film thickness on the microstructural, piezoelectric and dielectric properties of AlN is investigated. An improved crystal quality with respect to the increased film thickness was observed; where full width at half maximum (FWHM) of the AlN films decreased from 2.88 ± 0.16° down to 1.25 ± 0.07° and the effective longitudinal piezoelectric coefficient (d33,f) increased from 2.30 ± 0.32 pm/V up to 5.57 ± 0.34 pm/V for film thicknesses in the range of 30 nm to 2 μm. Dielectric loss angle (tan δ) decreased from 0.626% ± 0.005% to 0.025% ± 0.011% for the same thickness range. The average relative permittivity (er) was calculated as 10.4 ± 0.05. An almost constant transversal piezoelectric coefficient (|e31,f|) of 1.39 ± 0.01 C/m2 was measured for samples in the range of 0.5 μm to 2 μm. Transmission electron microscopy (TEM) investigations performed on thin (100 nm) and thick (1.6 μm) films revealed an (002) oriented AlN nucleation and growth starting directly from the AlN-Pt interface independent of the film thickness and exhibit comparable quality with the state-of-the-art AlN thin films sputtered at much higher substrate temperatures.
Extracted statement — Piezoelectric coefficient measured (pm/V): 5.57
Research field: Engineering
Title: Enhancement of c-Axis Oriented Aluminum Nitride Films via Low Temperature DC Sputtering
Abstract: In this study, we successfully deposit c-axis oriented aluminum nitride (AlN) piezoelectric films at low temperature (100 °C) via the DC sputtering method with tilt gun. The X-ray diffraction (XRD) observations prove that the deposited films have a c-axis preferred orientation. Effective d33 value of the proposed films is 5.92 pm/V, which is better than most of the reported data using DC sputtering or other processing methods. It is found that the gun placed at 25° helped the films to rearrange at low temperature and c-axis orientation AlN films were successfully grown at 100 °C. This temperature is much lower than the reported growing temperature. It means the piezoelectric films can be deposited at flexible substrate and the photoresist can be stable at this temperature. The cantilever beam type microelectromechanical systems (MEMS) piezoelectric accelerometers are then fabricated based on the proposed AlN films with a lift-off process. The results show that the responsivity of the proposed devices is 8.12 mV/g, and the resonance frequency is 460 Hz, which indicates they can be used for machine tools.
Extracted statement — Piezoelectric coefficient measured (pm/V): 5.92
Research field: Engineering
Title: Hybrid Perovskite Films by a New Variant of Pulsed Excimer Laser Deposition: A Room-Temperature Dry Process
Abstract: A new variant of the classic pulsed laser deposition (PLD) process is introduced as a room-temperature dry process for the growth and stoichiometry control of hybrid perovskite films through the use of nonstoichiometric single target ablation and off-axis growth. Mixed halide hybrid perovskite films nominally represented by CH3NH3PbI3–xAx (A = Cl or F) are also grown and are shown to reveal interesting trends in the optical properties and photoresponse. Growth of good quality lead-free CH3NH3SnI3 films is also demonstrated, and the corresponding optical properties are presented. Finally, perovskite solar cells fabricated at room temperature (which makes the process adaptable to flexible substrates) are shown to yield a conversion efficiency of about 7.7%.
Extracted statement — Maximum efficiency of the solar cell  (%): 7.7
Research field: Engineering
Title: Highly Stretchable Resistive Pressure Sensors Using a Conductive Elastomeric Composite on a Micropyramid Array
Abstract: A stretchable resistive pressure sensor is achieved by coating a compressible substrate with a highly stretchable electrode. The substrate contains an array of microscale pyramidal features, and the electrode comprises a polymer composite. When the pressure-induced geometrical change experienced by the electrode is maximized at 40% elongation, a sensitivity of 10.3 kPa(-1) is achieved.
Extracted statement — Sensitivity (/kPa): 10.3
Research field: Engineering
Title: Highly Efficient and Stable Sn-Rich Perovskite Solar Cells by Introducing Bromine
Abstract: Compositional engineering of recently arising methylammonium (MA) lead (Pb) halide based perovskites is an essential approach for finding better perovskite compositions to resolve still remaining issues of toxic Pb, long-term instability, etc. In this work, we carried out crystallographic, morphological, optical, and photovoltaic characterization of compositional MASn0.6Pb0.4I3-xBrx by gradually introducing bromine (Br) into parental Pb-Sn binary perovskite (MASn0.6Pb0.4I3) to elucidate its function in Sn-rich (Sn:Pb = 6:4) perovskites. We found significant advances in crystallinity and dense coverage of the perovskite films by inserting the Br into Sn-rich perovskite lattice. Furthermore, light-intensity-dependent open circuit voltage (Voc) measurement revealed much suppressed trap-assisted recombination for a proper Br-added (x = 0.4) device. These contributed to attaining the unprecedented power conversion efficiency of 12.1% and Voc of 0.78 V, which are, to the best of our knowledge, the highest performance in the Sn-rich (≥60%) perovskite solar cells reported so far. In addition, impressive enhancement of photocurrent-output stability and little hysteresis were found, which paves the way for the development of environmentally benign (Pb reduction), stable monolithic tandem cells using the developed low band gap (1.24-1.26 eV) MASn0.6Pb0.4I3-xBrx with suggested composition (x = 0.2-0.4).
Extracted statement — Maximum efficiency of the solar cell  (%): 12.1
Research field: Engineering
Title: Stable Low-Bandgap Pb-Sn Binary Perovskites for Tandem Solar Cells
Abstract: A low-bandgap (1.33 eV) Sn-based MA0.5 FA0.5 Pb0.75 Sn0.25 I3 perovskite is developed via combined compositional, process, and interfacial engineering. It can deliver a high power conversion efficiency (PCE) of 14.19%. Finally, a four-terminal all-perovskite tandem solar cell is demonstrated by combining this low-bandgap cell with a semitransparent MAPbI3 cell to achieve a high efficiency of 19.08%.
Extracted statement — Maximum efficiency of the solar cell  (%): 14.19
Research field: Engineering
Title: Fabrication of Efficient Low-Bandgap Perovskite Solar Cells by Combining Formamidinium Tin Iodide with Methylammonium Lead Iodide
Abstract: Mixed tin (Sn)-lead (Pb) perovskites with high Sn content exhibit low bandgaps suitable for fabricating the bottom cell of perovskite-based tandem solar cells. In this work, we report on the fabrication of efficient mixed Sn-Pb perovskite solar cells using precursors combining formamidinium tin iodide (FASnI3) and methylammonium lead iodide (MAPbI3). The best-performing cell fabricated using a (FASnI3)0.6(MAPbI3)0.4 absorber with an absorption edge of ∼1.2 eV achieved a power conversion efficiency (PCE) of 15.08 (15.00)% with an open-circuit voltage of 0.795 (0.799) V, a short-circuit current density of 26.86(26.82) mA/cm(2), and a fill factor of 70.6(70.0)% when measured under forward (reverse) voltage scan. The average PCE of 50 cells we have fabricated is 14.39 ± 0.33%, indicating good reproducibility.
Extracted statement — Maximum efficiency of the solar cell  (%): 15.08
Research field: Engineering
Title: Sensitivity-Enhanced Fiber Temperature Sensor Based on Vernier Effect and Dual In-Line Mach–Zehnder Interferometers
Abstract: A highly sensitive fiber temperature sensor based on in-line Mach-Zehnder interferometers (MZIs) and Vernier effect was proposed and experimentally demonstrated. The MZI was fabricated by splicing a section of hollow core fiber between two pieces of multimode fiber. The temperature sensitivity obtained by extracting envelope dip shift of the superimposed spectrum reaches to 528.5 pm/°C in the range of 0 °C–100 °C, which is 17.5 times as high as that without enhanced by the Vernier effect. The experimental sensitivity amplification factor is close to the theoretical predication (18.3 times).The proposed sensitivity enhancement system employs parallel connecting to implement the Vernier effect, which possesses the advantages of easy fabrication and high flexibility.
Extracted statement — Amplification factor: 17.5
Research field: Engineering
Title: Performance Investigation of an n-Type Tin-Oxide Thin Film Transistor by Channel Plasma Processing
Abstract: In this paper, we investigated the performance of an n-type tin-oxide (SnOx) thin film transistor (TFT) by experiments and simulation. The fabricated SnOx TFT device by oxygen plasma treatment on the channel exhibited n-type conduction with an on/off current ratio of 4.4x104, a high field-effect mobility of 18.5 cm2/V.s and a threshold swing of 405 mV/decade, which could be attributed to the excess reacted oxygen incorporated to the channel to form the oxygen-rich n-type SnOx. Furthermore, a TCAD simulation based on the n-type SnOx TFT device was performed by fitting the experimental data to investigate the effect of the channel traps on the device performance, indicating that performance enhancements were further achieved by suppressing the density of channel traps. In addition, the n-type SnOx TFT device exhibited high stability upon illumination with visible light. The results show that the n-type SnOx TFT device by channel plasma processing has considerable potential for next-generation high-performance display application.
Extracted statement — Mobility (cm2 /V.s): 18.5
Research field: Engineering
Title: Efficiently Improving the Stability of Inverted Perovskite Solar Cells by Employing Polyethylenimine-Modified Carbon Nanotubes as Electrodes
Abstract: Inverted perovskite solar cells (PSCs) have been becoming more and more attractive, owing to their easy-fabrication and suppressed hysteresis, while the ion diffusion between metallic electrode and perovskite layer limit the long-term stability of devices. In this work, we employed a novel polyethylenimine (PEI) modified cross-stacked superaligned carbon nanotube (CSCNT) film in the inverted planar PSCs configurated FTO/NiO x/methylammonium lead tri-iodide (MAPbI3)/6, 6-phenyl C61-butyric acid methyl ester (PCBM)/CSCNT:PEI. By modifying CSCNT with a certain concentration of PEI (0.5 wt %), suitable energy level alignment and promoted interfacial charge transfer have been achieved, leading to a significant enhancement in the photovoltaic performance. As a result, a champion power conversion efficiency (PCE) of ∼11% was obtained with a Voc of 0.95 V, a Jsc of 18.7 mA cm-2, a FF of 0.61 as well as negligible hysteresis. Moreover, CSCNT:PEI based inverted PSCs show superior durability in comparison to the standard silver based devices, remaining over 85% of the initial PCE after 500 h aging under various conditions, including long-term air exposure, thermal, and humid treatment. This work opens up a new avenue of facile modified carbon electrodes for highly stable and hysteresis suppressed PSCs.
Extracted statement — Short-circuit current density, Jsc (mA/cm2): 18.7
Research field: Engineering
Title: Efficient perovskite solar cells by metal ion doping
Abstract: Realizing the theoretical limiting power conversion efficiency (PCE) in perovskite solar cells requires a better understanding and control over the fundamental loss processes occurring in the bulk of the perovskite layer and at the internal semiconductor interfaces in devices. One of the main challenges is to eliminate the presence of charge recombination centres throughout the film which have been observed to be most densely located at regions near the grain boundaries. Here, we introduce aluminium acetylacetonate to the perovskite precursor solution, which improves the crystal quality by reducing the microstrain in the polycrystalline film. At the same time, we achieve a reduction in the non-radiative recombination rate, a remarkable improvement in the photoluminescence quantum efficiency (PLQE) and a reduction in the electronic disorder deduced from an Urbach energy of only 12.6 meV in complete devices. As a result, we demonstrate a PCE of 19.1% with negligible hysteresis in planar heterojunction solar cells comprising all organic p and n-type charge collection layers. Our work shows that an additional level of control of perovskite thin film quality is possible via impurity cation doping, and further demonstrates the continuing importance of improving the electronic quality of the perovskite absorber and the nature of the heterojunctions to further improve the solar cell performance.
Extracted statement — Maximum efficiency of the solar cell  (%): 19.1