The protection from the effects of gamma rays of metal-semiconductor diodes by means of ZnO thin interface layer

In this study, the protective effects of Zinc oxide (ZnO) interfacial layer in the Zn/n-Si rectifying contacts against gamma radiation were investigated. In the fabrication of the diodes, n-type Si is used as a semiconductor. First, an ohmic contact is made by using Au-Sb alloy on the polished surface of the n-Si. Afterwards, the ZnO thin film is grown on the n-type Si semiconductor substrate by the RF magnetron sputtering technique. The structural properties of ZnO thin films are investigated by x-ray diffraction (XRD) measurements. It is found that ZnO films are polycrystalline. Current-voltage (I-V) measurements of Zn/n-Si/Au-Sb and Zn/ZnO/n-Si/Au--Sb diodes which are fabricated under laboratory conditions are taken at room temperature in the dark. The basic electrical parameters such as ideality factor (n), barrier height (Phi(b), series resistance (R-s), rectifying ratio (RR) and interface state density (N-ss) of diodes are calculated from the forward bias I-V characteristics. To examine the effects of gamma radiation on the electrical parameters, the diodes are exposed to gamma rays using barium-133, americium-241, and cobalt-60 gamma sources. After irradiation, I-V measurements of diodes are taken again, the characteristic parameters are calculated and the results are compared with the previous ones.