Stability Studies of Hydrogenated Amorphous Silicon Alloy Solar Cells Prepared with Hydrogen Dilution

1994 ◽  
Vol 336 ◽  
Author(s):  
J. Yang ◽  
X. Xu ◽  
S. Guha

ABSTRACTWe have fabricated hydrogenated amorphous silicon alloy solar cells using hydrogen dilutions at 175 °C and 300 °C, and obtained improved photovoltaic characteristics in both the initial and degraded states for the highly diluted cells; both the fill factor and the open-circuit voltage exhibit higher values before and after light soaking. Infrared analyses reveal that for a given deposition temperature the amount of bonded hydrogen has similar concentrations between the high and low hydrogen diluted samples. Optical Modelling shows a 20 MeV difference in their optical bandgap. Defect densities obtained from constant photocurrent measurements give similar values for a given deposition temperature both before and after light soaking, inconsistent with solar cell performance.

2012 ◽  
Vol 1439 ◽  
pp. 145-150
Author(s):  
Yasuyoshi Kurokawa ◽  
Shinya Kato ◽  
Yuya Watanabe ◽  
Akira Yamada ◽  
Makoto Konagai ◽  
...  

ABSTRACTThe electrical characteristics of silicon nanowire (SiNW) solar cells with p-type hydrogenated amorphous silicon oxide (Eg=1.9 eV)/n-type SiNWs embedded in SiO2/n-type hydrogenated amorphous silicon (Eg=1.7 eV) structure have been investigated using a two-dimensional device simulator with taking the quantum size effects into account. The average bandgap of a SiNW embedded in SiO2 increased from 1.15 eV to 2.71 eV with decreasing the diameter from 10 nm to 1 nm due to the quantum size effect. It should be noted that under the sunlight with AM1.5G the open-circuit voltage (Voc) of SiNW solar cells also increased to 1.54 V with decreasing the diameter of the SiNWs to 1 nm. This result suggests that it is possible to enhance the Voc by the quantum size effect and a SiNW is a promising material for the all silicon tandem solar cells.


Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 402 ◽  
Author(s):  
Chia-Hsun Hsu ◽  
Xiao-Ying Zhang ◽  
Ming Jie Zhao ◽  
Hai-Jun Lin ◽  
Wen-Zhang Zhu ◽  
...  

Boron-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films are deposited using high frequency 27.12 MHz plasma enhanced chemical vapor deposition system as a window layer of silicon heterojunction (SHJ) solar cells. The CH4 gas flow rate is varied to deposit various a-SiC:H films, and the optical and electrical properties are investigated. The experimental results show that at the CH4 flow rate of 40 sccm the a-SiC:H has a high band gap of 2.1 eV and reduced absorption coefficients in the whole wavelength region, but the electrical conductivity deteriorates. The technology computer aided design simulation for SHJ devices reveal the band discontinuity at i/p interface when the a-SiC:H films are used. For fabricated SHJ solar cell performance, the highest conversion efficiency of 22.14%, which is 0.33% abs higher than that of conventional hydrogenated amorphous silicon window layer, can be obtained when the intermediate band gap (2 eV) a-SiC:H window layer is used.


2005 ◽  
Vol 862 ◽  
Author(s):  
Jianjun Liang ◽  
E. A. Schiff ◽  
S. Guha ◽  
B. Yan ◽  
J. Yang

AbstractWe present temperature-dependent measurements of the open-circuit voltage VOC(T) in hydrogenated amorphous silicon nip solar cells prepared at United Solar. At room-temperature and above, VOC measured using near-solar illumination intensity differs by as much as 0.04 V for the as-deposited and light-soaked states; the values of VOC for the two states converge below 250 K. Models for VOC based entirely on recombination through deep levels (dangling bonds) do not account for the convergence effect. The convergence is present in a model that assumes the recombination traffic in the as-deposited state involves only bandtails, but which splits the recombination traffic fairly evenly between bandtails and defects for the light-soaked state at room-temperature. Recombination mechanisms are important in understanding light-soaking, and the present results are inconsistent with at least one well-known model for defect generation.


2009 ◽  
Vol 1153 ◽  
Author(s):  
Anatoli Shkrebtii ◽  
Yuriy Kryuchenko ◽  
Anaroliy Sachenko ◽  
Igor Sokolovskyi ◽  
Franco Gaspari

AbstractThin film hydrogenated amorphous silicon (a-Si:H) is widely used in photovoltaics. In order to get the best possible performance of the a-Si:H solar cells it is important to optimize the amorphous film and solar cells in terms their parameters such as mobility gap, p-, i- and n-layer doping levels, electron and hole lifetime and their mobilities, resistance of p-, i- and n-layers, contact grid geometry and parameters of the transparent conducting and antireflecting layers, and others. To maximize thin a-Si:H film based solar cell performance we have developed a general numerical formalism of photoconversion, which takes into account all the above parameters for the optimization. Application of the formalism is demonstrated for typical a-Si:H based solar cells before Staebler-Wronski (SW) light soaking effect. This general formalism is not limited to a-Si:H based systems only, and it can be applied to other types of solar cells as well.


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