Photocreation processes for neutral dangling bonds in a-Ge-N:H compared with a-Si-N:H

Abstract The structure of defects and photocreation processes for neutral dangling bonds are studied in a-Ge 1− x N x :H with various x , and the results are compared with those in a-Si 1− x N x :H. In both a-Ge 1− x N x :H and a-Si 1− x N x :H with a medium range of x , neutral dangling bonds are created by bandgap illumination through two separate processes. One of them is a rapid process which we attribute to carrier capture at pre-existing charged dangling bonds. The other is a slower process which we assume to be bond breaking. When x approaches the stoichiometric composition, the creation process by illumination begins a monotonic increase, but we suggest that it also consists of these two processes.