High current fast switching n-ZnO/p-Si diode

The authors report on the high current density n-ZnO/p-Si heterojunction diode that has been fabricated by atomic layer deposition (ALD) of 70 nm thin ZnO on a p-Si substrate. While the diode was formed at four different ALD temperatures of 80, 100, 150 and 200 °C, the 100 °C processed diode showed an optimal behaviour of an on-off ratio over 3.3 × 10³ and a high forward current density, ∼300A cm^-2 at 3V. Although the highest film conductance appeared from the 200 °C deposited ZnO layer, nanometre thin SiO_x was also revealed at the ZnO/p-Si interface; it might cause a high reverse leakage current level. Our high current density diode also demonstrates a fast switching performance without any reverse recovery delay, which is often observed at a usual Si p-n diode.