"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

GAP-STATE SPECTROSCOPY IN AMORPHOUS SELENIUM

M. L. Benkhedir1,* , M. Brinza1, J. Willekens1, K. Haenen2, M. Daenen2, M. Nesladek2, G. J. Adriaenssens1

Affiliation

  1. University of Leuven, Halfgeleiderfysica, Celestijnenlaan 200D, B-3001 Leuven, Belgium
  2. Institute of Materials Research, Limburgs Universitair Centrum, B-3590 Diepenbeek, Belgium

Abstract

Through a combination of steady-state and transient photocurrent spectroscopy it has been possible to locate several of the energy levels of the charged coordination defects (D+ and D-) that constitute the chalcogenide negative-U model in the amorphous selenium bandgap. However it has also been observed that the energy position of those levels is influenced by external influences such as light soaking or annealing of the samples. The post-transit time of-flight photocurrents that reveal those energy positions have, therefore, been systematically studied in samples with different pre-histories. The optical absorption in the samples was further examined through the constant-photocurrent method (CPM), and by photothermal deflection spectroscopy (PDS). Although the TOF results provide information on the D+ and D- levels separately, while the CPM and PDS data reflect the integral optical absorption between both centres and the bands, the results do agree. The photo-induced changes that are observed are stable at room temperature..

Keywords

Amorphous selenium, Gap states, Photoconductivity, Photothermal deflection spectroscopy.

Submitted at: Aug. 25, 2005
Accepted at: Sept. 22, 2005

Citation

M. L. Benkhedir, M. Brinza, J. Willekens, K. Haenen, M. Daenen, M. Nesladek, G. J. Adriaenssens, GAP-STATE SPECTROSCOPY IN AMORPHOUS SELENIUM, Journal of Optoelectronics and Advanced Materials Vol. 7, Iss. 5, pp. 2223-2230 (2005)