Changes in the defect density of hydrogenated amorphous thin-film structures, due to the use of prolonged bias stresses or light soaking, were studied by using photocurrent measurements. The photocurrent absorption due to defect absorption did not change after positive or negative bias stressing. On the other hand, the photocurrent absorption due to dangling-bond defects increased markedly after light soaking. These results demonstrated that the bulk defect density of amorphous hydrogenated material in thin-film structures was not changed by long-term bias stressing.

H.R.Park, D.S.Oh, J.Jang: Applied Physics Letters, 1996, 68[22], 3135-7