EFFECT OF H-CONTENT AND H-BONDING CONFIGURATION ON LIGHT AND THERMAL INDUCED METASTABILITY IN AMORPHOUS HYDROGENATED GERMANIUM (A-GE-H)

Reversible changes of sigma(d) and sigma(ph) in a-Ge:H after light deg radation and thermal quenching have been investigated. Quantitatively these two methods of defect generation cause very different changes of sigma: Light degradation effects are dependent on light intensity. Hi gh intensity decreases sigma(ph) by about 10 %. Fast thermal quenching lowers sigma(d) and sigma(ph) by a factor of 2-3. Qualitatively the t wo different ways of degradation yield similar defect kinetics which c an be described by a stretched exponential. This implies common micros copic defect reactions. The equilibration temperature as well as the r elaxation time is strongly dependent on hydrogen content. Combining IR spectroscopy, which gives information about hydrogen bonding configur ation, and thermal quenching experiments indicates that mainly H on in ner surfaces influence metastable effects in a-Ge:H.