Electrical transport modulation of VO2/Si(111) heterojunction by engineering interfacial barrier height

Abstract

Smart multifunctional materials such as vanadium dioxide (VO2), which exhibit a reversible semiconductor-to-metal transition (SMT), provide a new route toward engineering high speed switchable devices. Here, we present a detailed report on the modulation in the electrical properties of VO2/Si heterostructures by application of an external electrical field across VO2 thin films. Single-phase VO2 thin films have been deposited on an Si(111) substrate using the pulsed laser deposition technique. The electrical transport behavior across the VO2/Si heterostructure has been studied in the temperature range of 35–105 °C, and a reversible SMT can be seen at 68 and 63 °C for heating and cooling cycles, respectively. The temperature-dependent resistance of the device shows a hysteresis loop around the transition temperature of the VO2 thin film. In addition, the device shows a significant change in junction current when an external bias is applied on the VO2 thin film, and this phenomenon has been utilized to study the switching behavior of the device. Such behavior is due to the change in interfacial barrier height because of the bias dependent tilting of electronic energy bands of the VO2 thin film. Our results offer novel opportunities to externally control the electrical transport of vertical heterostructures and can be beneficial for extending the notion of electrical field modulation in electrical switches and sensors.