Comparison between ESR and CPM for the Gap States in a-Si-Ge:H

Abstract
Si dangling bonds and Ge dangling bonds in a-Si1-x Ge x :H are separately estimated both by low-energy optical absorption measurements using a constant photocurrent method (CPM) and by ESR measurements. The ratio of the density of Si dangling bonds to that of Ge dangling bonds decreases with increasing germanium content, as expected. However, the ratio deduced from CPM is far larger than that deduced from ESR. Origins of the difference are discusssed.