INFLUENCE OF X-RAY-EXPOSURE ON ELECTRICAL-PROPERTIES OF A-SI-H LAYERS

Soft X-ray induced changes in electrical and photoelectric properties of a-Si:H layers are investigated. Two groups of samples are distingui shed. Samples of the first group sputtered at high substrate temperatu res show a decrease and samples of the second group prepared at low su bstrate temperatures an increase of the dark conductivity after irradi ation. In all samples the neutral dangling bond density increases and the photoconductivity decreases induced by the exposure. Spectroscopic investigations of the hydrogen incorporation show a correlation betwe en hydrogen bonded in microvoids and the degree of degradation of dark conductivity. The formation of neutral dangling bonds is discussed as the cause of the behaviour of group 1. Otherwise in samples of group 2 a recharging of defects after exposure controlled by the microstruct ure of the a-Si:H layers is assumed.