The Movement of Mobility Edges in Hydrogenated Amorphous Silicon

1990 ◽  
Vol 192 ◽  
Author(s):  
S. Lee ◽  
D. Heller ◽  
C. R Wronski

ABSTRACTInternal photoemission of both electrons and holes is used to investigate the movement of the mobility edges in high quality intrinsic, undoped hy-drogenated amorphous silicon (a-Si:H) with temperature and electrical field. The electron mobility edge is found to move up in energy by ∼40meV between 298K and 120K. On the other hand, the hole mobility edge remains essentially unchanged between 298K and 160K. The injection (and collection) of photoemitted holes is less efficient than that for electrons and in the films studied could not be measured below 160K.

2003 ◽  
Vol 762 ◽  
Author(s):  
Guofu Hou ◽  
Xinhua Geng ◽  
Xiaodan Zhang ◽  
Ying Zhao ◽  
Junming Xue ◽  
...  

AbstractHigh rate deposition of high quality and stable hydrogenated amorphous silicon (a-Si:H) films were performed near the threshold of amorphous to microcrystalline phase transition using a very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of hydrogen dilution on optic-electronic and structural properties of these films was investigated by Fourier-transform infrared (FTIR) spectroscopy, Raman scattering and constant photocurrent method (CPM). Experiment showed that although the phase transition was much influenced by hydrogen dilution, it also strongly depended on substrate temperature, working pressure and plasma power. With optimized condition high quality and high stable a-Si:H films, which exhibit σph/σd of 4.4×106 and deposition rate of 28.8Å/s, have been obtained.


1989 ◽  
Vol 149 ◽  
Author(s):  
Richard. S. Crandall ◽  
Kyle Sadlon ◽  
Jeffrey Kalina ◽  
Alan E. Delahoy

ABSTRACTDirect measurements of the electron and hole mobility-lifetime products, μτ, on a 10μm thick hydrogenated amorphous silicon (a-Si:H) pi- n solar cell are presented. The μτ products, determined from charge collection using strongly absorbed light are μτ|h = 2.2 × 10−8cm2V−1 and μτ|e = 3.0 × 10−7cm2V−1, for holes,and electrons, respectively. Measurements of the drift length, ld = μτ|e + μτ|h, using uniformly absorbed light and analyzed using the uniform field model,1 give ld = 2.9 × 10−7 cm2 V−1 s−1. These results are the first experimental evidence that the carrier with the larger, μτ product determines the photovoltaic behavior. Evidence for space charge limited transport of photogenerated holes is also be presented.


2011 ◽  
Vol 99 (20) ◽  
pp. 203503 ◽  
Author(s):  
Jan-Willem A. Schüttauf ◽  
Karine H. M. van der Werf ◽  
Inge M. Kielen ◽  
Wilfried G. J. H. M. van Sark ◽  
Jatindra K. Rath ◽  
...  

2014 ◽  
Vol 92 (7/8) ◽  
pp. 586-588 ◽  
Author(s):  
Y. Kitani ◽  
T. Maeda ◽  
S. Kakimoto ◽  
K. Tanaka ◽  
R. Okumoto ◽  
...  

Boron-doping characteristics in hydrogenated amorphous silicon–oxygen alloys (a-SiO:H) have been studied in contrast to those in hydrogenated amorphous silicon (a-Si:H). Although the boron-incorporation efficiency shows almost the same value between a-SiO:H and a-Si:H, p-type a-SiO:H (p-a-SiO:H) exhibits lower dark conductivity by one or two orders of magnitude as compared to p-type a-Si:H (p-a-Si:H) in a wide range of doping levels. We have found that p-a-SiO:H exhibits low dark conductivity as compared to p-a-Si:H even when we choose samples showing the same activation energy from a variety of as-deposited and thermally annealed samples. We have concluded from the different Urbach-energy values between high quality intrinsic a-SiO:H and a-Si:H that the origin of low dark conductivity in p-a-SiO:H is due to low hole mobility.


1996 ◽  
Vol 420 ◽  
Author(s):  
W. Futako ◽  
I. Shimizu ◽  
C. M. Fortmann

AbstractHydrogenated amorphous silicon (a-Si:H) with a gaps narrower than 1.7 eV were made by repeating the deposition of a thin layer (1–3 nm thick) and the treatment of growing surface with a mixture of H and Ar*. Crystallization induced by permeation of hydrogen into the subsurface at high substrate temperature (>200C) was efficiently prevented by treating with a mixture of H and Ar*. The activation of growing surface may arise from releasing a part of hydrogen on surface by treating with Ar*. High quality a-Si:H films containing hydrogen of 3 atom % with a gap of 1.6 eV were made by chemical annealing with a mixture of H and Ar*.


1994 ◽  
Vol 33 (Part 1, No. 4A) ◽  
pp. 1773-1777 ◽  
Author(s):  
Shingo Okamoto ◽  
Yoshihiro Hishikawa ◽  
Sadaji Tsuge ◽  
Manabu Sasaki ◽  
Kunimoto Ninomiya ◽  
...  

1990 ◽  
Vol 57 (5) ◽  
pp. 484-486 ◽  
Author(s):  
Akira Yoshida ◽  
Katsushi Inoue ◽  
Haruhiko Ohashi ◽  
Yoji Saito

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