Transport mechanisms and photovoltaic characterizations of spray-depositedof CdS on InP in heterojunction devices

n-CdS/p-InP heterojunctions have been fabricated by deposition of n-CdS thi n films using a spray pyrolysis technique onto p-type InP[100]. Current den sity-voltage and capacitance-voltage measurements were performed to determi ne the electrical properties of the structures. The forward current involve s tunneling and is explained by a multi-tunneling capture-emission model. T he reverse current is limited by the carrier generation process. The capaci tance-voltage behavior indicates an abrupt interface with a main-band disco ntinuity of 0.76 eV occurs in the valence band. Effect of InP doping densit y on photovoltaic parameters has also been investigated at different light intensities. The devices exhibit a maximum power conversion efficiency (up to 12%) using an optimum doping density of 1 x 10(15) cm(-3). (C) 2001 Else vier Science B.V. All rights reserved.