Kinetics of light-induced metastable defect creation and annealing in a-Si:H


Kodolbaş A. O. , ERAY A., Öktü Ö.

Turkish Journal of Physics, vol.26, no.1, pp.33-39, 2002 (Peer-Reviewed Journal) identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 1
  • Publication Date: 2002
  • Journal Name: Turkish Journal of Physics
  • Journal Indexes: Science Citation Index Expanded, Scopus, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.33-39
  • Keywords: a-Si:H, CPM, Distribution of annealing activation energies, Light induced metastable defect, Photoconductivity, Staebler-Wronski effect

Abstract

Constant Photocurrent Method (CPM) and steady state photoconductivity measurements are used to investigate the creation of light-induced metastable defects in a-Si:H at room temperature and their annealing. Light-induced metastable defect concentration Nd varies with exposure time te as tcr with r=0.344±0.02, as expected from the recombination induced weak bond breaking model. The validity of a stretched exponential model is also studied. From the annealing experiments, the distribution of thermal annealing activation energies is calculated following the method proposed by Hata and Wagner. Defects created at room temperature show a narrow distribution of annealing activation energies peaking at 0.97eV. The relation between photoconductivity and Nd is strongly nonlinear. Defects created at earlier times of illumination degrade photoconductivity more strongly, and these defects anneal out more easily than those created at later times of illumination.