Study of the electrical and junction properties of ITO thin films deposited on CdTe and InP substrates

Thin films of indium tin oxide (ITO) have been deposited on fused quartz substrates by the spray deposition and rf-magnetron sputtering methods and their optical and electrical properties investigated. The junction properties of fabricated ITO/pCdTe and ITO/pInP structures have also been studied and their electrical properties presented. It is established that the deposited ITO films have a lattice constant of 10.14 Å and grow in cubic modifications along the (400) direction. Their transmittance value rises up to between 85% and 90% and extends well beyond the visible range of the spectrum. In the forward direction of the ITO/pCdTe structure, it is suggested that tunnelling dominated processes determine the current flow mechanism. Recombination currents at the interface region and thermionic-emission currents, however, dominate in the ITO/pInP structure at low bias and high bias respectively. The two structures can best be described as heterojunctions.