Photothermoelectric Analysis of Chemically Deposited Cadmium Sulfide Layers

Carrier mobilities in the few thousandths cm2/V sec can be reliably inferred from thermoelectric power measurements, considerably smaller than can be determined by standard Hall measurements. Techniques of photothermoelectric analysis are applied to chemically deposited layers of CdS and CdS–CdSe, as prepared, and after photosensitization by impurity diffusion. Photoconductivity in the unsensitized films is due wholly to an increase in mobility; in the sensitized films, both carrier density and mobility increase with photoexcitation. The high-light mobility is increased by a factor of 102 by impurity sensitization.