The physical reason of intense electroluminescence in ITO-Si heterostructures

Intense electroluminescence from a spray deposited heavily tin-doped indium oxide (ITO)-n type silicon (Si) heterojunctions, presenting the properties of an induced p-n junction, has been observed. The role of the degenerated n-type ITO film as a good supplier of holes to maintain an inversion layer formed at the silicon interface is discussed. However, the physical mechanism responsible for a significantly higher quantum efficiency of the radiation emission from such structures is not clear. The explanation of this phenomenon, based on the confinement of carriers at the interface due to multi-point contacts between the ITO film and the silicon, is discussed.