Analysis and simulation of Si/GaAs/GaN MESFET to study the impact of localised charges on device performance

Author(s):  
R Gautam ◽  
M Saxena ◽  
M Gupta ◽  
R S Gupta
2001 ◽  
Vol 664 ◽  
Author(s):  
C. Y. Wang ◽  
E. H. Lim ◽  
H. Liu ◽  
J. L. Sudijono ◽  
T. C. Ang ◽  
...  

ABSTRACTIn this paper the impact of the ESL (Etch Stop layer) nitride on the device performance especially the threshold voltage (Vt) has been studied. From SIMS analysis, it is found that different nitride gives different H concentration, [H] in the Gate oxide area, the higher [H] in the nitride film, the higher H in the Gate Oxide area and the lower the threshold voltage. It is also found that using TiSi instead of CoSi can help to stop the H from diffusing into Gate Oxide/channel area, resulting in a smaller threshold voltage drift for the device employed TiSi. Study to control the [H] in the nitride film is also carried out. In this paper, RBS, HFS and FTIR are used to analyze the composition changes of the SiN films prepared using Plasma enhanced Chemical Vapor deposition (PECVD), Rapid Thermal Chemical Vapor Deposition (RTCVD) with different process parameters. Gas flow ratio, RF power and temperature are found to be the key factors that affect the composition and the H concentration in the film. It is found that the nearer the SiN composition to stoichiometric Si3N4, the lower the [H] in SiN film because there is no excess silicon or nitrogen to be bonded with H. However the lowest [H] in the SiN film is limited by temperature. The higher the process temperature the lower the [H] can be obtained in the SiN film and the nearer the composition to stoichiometric Si3N4.


Author(s):  
AnuPriya K R ◽  
Sasilatha T

The system represented during this paper uses 3 matrix converters and a high frequency electrical device to attain isolation and voltage transformation from primary to secondary aspect. Two matrix converters manufacture high frequency voltage across a transformer, with open all over primary. a 3rd matrix device converts the high frequency cut voltage to line frequency. The non-idealities like outflow inductance of the electrical device have a big impact on the device performance. This paper studies the impact of outflow inductance on the regulation of the output voltage of the device. The simulation study has been carried out in SIMULINK and also the results are presented.


2005 ◽  
Vol 863 ◽  
Author(s):  
Xiaopeng Xu ◽  
Victor Moroz

AbstractIn this study the stress evolution for the entire transistor fabrication process is simulated and the packaging stress is modeled as the external pressure/normal stress acting on the boundaries of the transistor unit cell. The impact on device performance from both the fabrication stress and the packaging stress is investigated using a classical piezo-resistance mobility model. The effect of the packaging stress on device mobility can be either beneficial or detrimental depending on whether the stress is tensile or compressive, on stress pattern, its magnitude, and the transistor type. The results suggest that utilizing both the fabrication stress and the packaging stress for stress engineering can lead to additional device performance enhancements.


Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 286 ◽  
Author(s):  
Dandan Zhao ◽  
Yinghui Wu ◽  
Bao Tu ◽  
Guichuan Xing ◽  
Haifeng Li ◽  
...  

Although a compact holes-transport-layer (HTL) film has always been deemed mandatory for perovskite solar cells (PSCs), the impact their compactness on the device performance has rarely been studied in detail. In this work, based on a device structure of FTO/CIGS/perovskite/PCBM/ZrAcac/Ag, that effect was systematically investigated with respect to device performance along with photo-physics characterization tools. Depending on spin-coating speed, the grain size and coverage ratio of those CIGS films on FTO substrates can be tuned, and this can result in different hole transfer efficiencies at the anode interface. At a speed of 4000 r.p.m., the band level offset between the perovskite and CIGS modified FTO was reduced to a minimum of 0.02 eV, leading to the best device performance, with conversion efficiency of 15.16% and open-circuit voltage of 1.04 V, along with the suppression of hysteresis. We believe that the balance of grain size and coverage ratio of CIGS interlayers can be tuned to an optimal point in the competition between carrier transport and recombination at the interface based on the proposed mechanism. This paper definitely deepens our understanding of the hole transfer mechanism at the interface of PSC devices, and facilitates future design of high-performance devices.


2018 ◽  
Vol 9 ◽  
pp. 649-659 ◽  
Author(s):  
Furqan Almyahi ◽  
Thomas R Andersen ◽  
Nathan A Cooling ◽  
Natalie P Holmes ◽  
Matthew J Griffith ◽  
...  

In this study we have optimised the preparation conditions for large-volume nanoparticle inks, based on poly(3-hexylthiophene) (P3HT):indene-C60 multiadducts (ICxA), through two purification processes: centrifugal and crossflow ultrafiltration. The impact of purification is twofold: firstly, removal of excess sodium dodecyl sulfate (SDS) surfactant from the ink and, secondly, concentration of the photoactive components in the ink. The removal of SDS was studied in detail both by a UV–vis spectroscopy-based method and by surface tension measurements of the nanoparticle ink filtrate; revealing that centrifugal ultrafiltration removed SDS at a higher rate than crossflow ultrafiltration even though a similar filter was applied in both cases (10,000 Da M w cut-off). The influence of SDS concentration on the aqueous solar nanoparticle (ASNP) inks was investigated by monitoring the surface morphology/topography of the ASNP films using atomic force microscopy (AFM) and scanning electron microscopy (SEM) and photovoltaic device performance as a function of ultrafiltration (decreasing SDS content). The surface morphology/topography showed, as expected, a decreased number of SDS crystallites on the surface of the ASNP film with increased ultrafiltration steps. The device performance revealed distinct peaks in efficiency with ultrafiltration: centrifuge purified inks reached a maximum efficiency at a dilution factor of 7.8 × 104, while crossflow purified inks did not reach a maximum efficiency until a dilution factor of 6.1 × 109. This difference was ascribed to the different wetting properties of the prepared inks and was further corroborated by surface tension measurements of the ASNP inks which revealed that the peak efficiencies for both methods occurred for similar surface tension values of 48.1 and 48.8 mN m−1. This work demonstrates that addressing the surface tension of large-volume ASNP inks is key to the reproducible fabrication of nanoparticle photovoltaic devices.


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