Measurement of spatial distribution of transport-photocarriers in amorphous chalcogenide

A method for measuring the spatial distribution of photocarriers which are transported in amorphous chalcogenide is reported. The specimen is a double-layer system composed of an amorphous chalcogenide and another material with even higher mobility. The density of carriers at the interface between the two layers is estimated from the induced photocurrent in the time-of-flight measurement. Then, the spatial distribution can be determined by a combination of these values for the chalcogenides with different layer thicknesses. The experimental results for As 2 Se 98 and As 2 Se 3 agree well with the theoretical predictions.