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 degrees C, the 100 degrees C processed diode showed an optimal behaviour of an on-off ratio over 3.3 x 10(3) and a high forward current density, similar to 300Acm(-2) at 3V. Although the highest film conductance appeared from the 200 degrees 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.