Hostname: page-component-7479d7b7d-pfhbr Total loading time: 0 Render date: 2024-07-11T09:23:40.537Z Has data issue: false hasContentIssue false
  • English
  • Français

A New Technique for Determining Midgap States and Hole Localization in a-Si:H Devices

Published online by Cambridge University Press:  25 February 2011

Vikarm L. Dalal  and
Ralph D. Knox
Vikarm L. Dalal
Affiliation:
Department of Electrical Engineering and Computer Engineering, Iowa State University Ames, IA 50011
Ralph D. Knox
Affiliation:
Microelectronics Research Center, Iowa State University Ames, IA 50011
Get access

Abstract

We describe a technique for measuring localization of holes in mid-gap states in high quality a-Si:H devices. The localization of holes is determined by measuring quantum efficiency of a-Si:H devices as a function of reverse bias voltage and wavelength of light. It is shown that the QE of localized holes increases significantly upon application of high electric fields, whereas the QE of de-localized holes does not show such a behavior. The voltage-induced increase in QE is explained using a Frenkel-Poole tunneling model. It is also shown that the density of mid-gap states (states in which holes are localized) increases significantly upon light soaking, and that a major consequence of this increase in mid-gap density is a decrease in the electric field in the device. The decrease in electric field is experimentally estimated by fitting the increased current due to tunneling to the expression for Frenkel-Poole tunneling.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 192: Symposium O – Amorphous Silicon Technology - 1990 , 1990 , 713
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Wronski, C., “Stability of A-Si Alloy Materials and Devices,’ (AIP Proc. #157, AIP, NY, 1987), p. 1.Google Scholar
Stutzmann, M., Jackson, W. B. and Tsai, C. C., Phys. Rev. B 32, 23 (1985).Google Scholar
[3] Gelatos, A. V. and Cohen, J. D., Proc. Mat’l Res. Society, Vol, 118, 141 (1988).Google Scholar
[4] Yamagishi, H., et al., AIP Proc., Vol. 157 , 111 (1987).Google Scholar
[5] Hack, M. and Shur, M., AIP Proc., Vol 157, 134 (1987).Google Scholar
[6] Vaseashta, A., Dalai, V. L., Gruenwald, A. and Halverson, W., Proc. IEEE Photovolt. Conf, (1985), p. 523.Google Scholar
[7] Catalano, A. W., et al., Proc. 19th IEEE Photovolt. Conf., (1987), pp. 1506.Google Scholar
[8] Phillips, J. E. and Roy, M., Proc. 20th IEEE Photovolt. Conf., (1988), pp. 1674.Google Scholar
[9] Dalai, V. L. and Alvarez, F., J. de Physics (Paris), 42 C-4, (1981), pp. 491.Google Scholar
[10] See, for example, Jaros, M., “Physics and Applications of Semiconductor Microstructures,” (Oxford, NY, 1989) pp. 119.Google Scholar
[11] Hack, M. and Shur, M., J. Appl. Phys., 58 , 1656 (1985).Google Scholar