Electrical properties of anisotype $n$-CdO/$p$-Si heterojunctions

An $n$-CdO/$p$-Si heterojunction is fabricated by the deposition of a thin cadmium-oxide film with $n$-type conductivity onto a polished polycrystalline $p$-Si wafer by the spray-pyrolysis technique. The I–V characteristics of the heterostructure are measured at different temperatures. It is established that the current through the investigated heterostructure at the forward bias $3kT/e < V <$ 0.5 V is formed by tunneling-recombination processes with the participation of surface states at the CdO/Si interface and at $V>$ 0.5 V, by tunneling through the space-charge region. The dominant mechanisms of current transport at reverse bias are the Frenkel–Pull emission and tunneling with the participation of energy levels formed by surface states.