Electrical characteristics of Mg doped GeO2 NWs based device

Abstract

In this article, the growth of a undoped GeO2 and Mg doped GeO2 nanowires (NWs) by electron beam evaporation method and analysis of its electrical properties has been reported. Au/GeO2 and Au/Mg-GeO2NWs based devices on Si substrate was fabricated. The optical band gap (Eg) for both the undoped GeO2 and Mg doped GeO2NWswas estimated to be 3.78 eV and 3.37 eV from UV–Vis spectrum. The temperature dependence current(I)–voltage(V) characteristics of undoped GeO2 based device shows a gradual increase of conductivity with the increase of temperature. Where, Mg doped GeO2NWs based device demonstrates a decreasing nature of conductivity with the increase of temperature. This anomalous characteristic has been explained by the positive temperature coefficient of resistance (PTCR) effect. The temperature dependent ideality factor of Mg doped GeO2NWsand undoped GeO2 NWs devices were studied. The increase in barrier height on increasing of temperature also been observed for the Mg doped GeO2NWs based device. Owing to the PTCR effect, the calculated series resistance of Mg doped GeO2NWs based device also shows an anomalous increasing behavior with the increasing of temperature where as undoped GeO2 based device shows a normal behavior of decreasing of series resistance with increase of temperature.