Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-10T10:09:33.389Z Has data issue: false hasContentIssue false
  • English
  • Français

Determination of the Density of States in Semiconductors from Transient Photoconductivity

Published online by Cambridge University Press:  15 February 2011

C. Main
C. Main*
Affiliation:
School of Engineering, University of Abertay Dundee, Bell Street, DUNDEE DD1 1HG, U.K., c.main@tay.ac.uk
Get access

Abstract

This paper discusses the techniques we have developed to analyse the photo-response of amorphous semiconductors to transient optical excitation to determine the energy distribution of gap states (DOS). We highlight the difficulties arising from a direct ‘single point’ approach using the instantaneous transient photocurrent i(t) when there is significant structure in the DOS or in the presence of recombination. Frequency domain methods which involve measurement of the amplitude I(ω) and phase φ(ω)of the steady ac photocurrent in response to ac excitation are shown to overcome these problems, but include other, experimental shortcomings. The paper describes a solution which combines the best features of time and frequency domain methods. The method involves numerical Fourier transformation of the time sampled impulse response i(tk) into a complex ac response (ω n), followed by analysis for gap-state distribution. Essentially, the method succeeds since it folds in information from the whole of the measured response for each energy considered. Other advantageous features include applicability to semiconductors exhibiting dispersive or non-dispersive transport, and to pre- and post- recombination regimes of the transient photocurrent, without modification. The features of this analytical method are demonstrated with computer simulated and experimental transient photocurrent data for a-Si:H.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 467: Symposium A – Amorphous and Microcrystalline Silicon Technology - 1997 , 1997 , 167
Copyright
Copyright © Materials Research Society 1997

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

1. Marshall, J.M., Rep. Prog. Phys. 46, 1235 (1983)Google Scholar
2. Nesladek, M., Triska, A. and Adriaenssens, G.J., J. Non-Cryst. Solids 141, 155 (1992)Google Scholar
3. Marshall, J.M., Street, R.A. and Thompson, M.J., Phil. Mag. B54, 51 (1986)Google Scholar
4. Marshall, J.M. and Main, C., Phil. Mag. B47, 471 (1983) 471 Google Scholar
5. Main, C., Brüggemann, R., Webb, D.P. and Reynolds, S., Solid State Comms. 83, 401 (1992)Google Scholar
6. Main, C., Berkin, J. and Marshall, J.M., in New Physical Problems in Electronic Materials, ed. Borisov, M., Kirov, N., Marshall, J.M. and Vavrek, A. (World Scientific, Singapore, 1990) p55 Google Scholar
7. Main, C. and Brüggemann, R., in Electronic and Optoelectronic Materials for the 21st Century. ed. Marshall, J.M., Kirov, N. and Vavrek, A. (World Scientific, Singapore, 1993) p270 Google Scholar
8. Arkhipov, V.I. and Rudenko, A.I., J. Non-Cryst. Solids 30, 168 (1978).Google Scholar
9. Main, C., Brüggemann, R., Webb, D.P. and Reynolds, S., J. Non-Cryst. Solids 164/166, 481 (1993)Google Scholar
10. Webb, D.P., Ph.D. thesis (University of Abertay Dundee 1994)Google Scholar
11. Hattori, K., Niwano, Y., Okamoto, H. and Hamakawa, Y., J. Non-Cryst. Solids 137/138, 363 (1991)Google Scholar
12. Naito, H., Ding, J. and Okuda, M., App. Phys. Lett., 64, 1830 (1993)Google Scholar
13. Naito, H., private communication.Google Scholar