EVIDENCE FOR CHARGED DEFECTS IN INTRINSIC GLOW-DISCHARGE HYDROGENATEDAMORPHOUS-SILICON-GERMANIUM ALLOYS

We have applied drive-level capacitance profiling, transient photocapa citance, and junction transient photocurrent measurements to character ize the defect-state distribution for a set of device-quality glow-dis charge a-Si,Ge:H films. The combination of the latter two methods can distinguish majority-from minority-carrier optical transitions. Compar ing the optical spectra of intrinsic samples with those in p-type and n-type samples, we have concluded that significant densities of positi vely and negatively charged deep defects exist in intrinsic glow-disch arge a-Si,Ge:H alloys. Our measurements also indicate how the density of these charged defects increase upon light-induced degradation and h ow they affect carrier recombination processes. [S0163-1829(98)52208-4 ].