On the influence of the thin interfacial oxide layer on the electrical and photovoltaic properties of Au/oxide/p-InP diodes

Au/thermal oxide/p-InP structures were investigated for the oxide layer thickness, delta , ranging from 1.8 to 13.5 nm. For increasing delta , the forward dark-current mechanism changed from thermionic emission into recombination, and tunnelling became dominant in reverse current. Under illumination the short-circuit current remained almost independent of delta up to 10 nm and an important increase of the open-circuit voltage occurred at delta >or=4.5 nm. Auger spectroscopy revealed that the outer part of the interfacial layer was In 2 O 3 while the inner part contained In, O and P. An energy band scheme was proposed for this two-layer model, which allowed the authors to explain the electrical characteristics.