An X-Ray Detector Based on a-Si: H/Transition Metal Bilayer Systems

Abstract

Photovoltaic measurements are performed on magnetron sputtered bilayer systems consisting of an amorphous hydrogenated silicon layer with a thickness of about 650 nm and a thin molybdenum or titanium layer. The open‐circuit voltage and the short‐circuit current are determined under white light illumination of a halogen lamp and X‐ray irradiation of a copper anode tube. The highest X‐ray induced signals are observed in bilayer systems containing a molybdenum layer with a thickness of about 15 nm. The voltages and currents generated under X‐ray irradiation increase monotonously with increasing exposure dose rate. The X‐ray sensitivity decreases exponentially with increasing tube anode voltage. The influence of the material and the thickness of the metal layers on the photovoltaic properties is discussed.