Properties of a-Se for use in flat panel X-ray image detectors

The present paper examines why a-Se has become the key photoconductor mater ial in flat panel direct conversion X-ray image detectors. We critically ex amine the X-ray sensitivity of stabilized a-Se layers as a function of elec tric field and mean photon energy. The radiation energy W+/- absorbed per f ree electron-hole pair liberated for photoconduction in both a-Se and a-Si: H seem to follow the Que-Rowlands rule of W+/- approximate to 2.2 E-g + E-p honon for amorphous semiconductors. (C) 2000 Elsevier Science B.V. All righ ts reserved.