P-Type α-CuGaO₂Electronics: A Study on Gap States and Fermi Level Pinning and a Solution to Schottky to Ohmic Transition for Electronic Applications

Delafossite CuGaO2 (CGO) as an emerging semiconductor is considered as a promising p-type material in electro-optics. The use of CGO in the semiconductor industry requires addressing the challenges encountering this material. One of the most significant issues in the technology development for the inclusive usage of this material is the proper choice of electrical connection. The Schottky barrier formed at the CGO/metal interface can be a restrictive and/or effective factor in electron transfer in electronic and electro-optical devices. In addition, the imperative Fermi level pinning (FLP) phenomenon makes the proper choice of the metal contact more thoughtful. In this research, we study the electronic properties of the CGO/metal interface and take into account the FLP phenomenon to select the appropriate metal contact for the required operation of the CGO-based devices. We look more closely at the Schottky to Ohmic connection transition. Technology computer-aided design (TCAD) simulations show that the FLP effect alters the Schottky barrier height (SBH) between CGO and the metal contact, reducing the dependence of the SBH on the metal’s work function. The hole concentration in CGO is varied between 1014 and 1021 cm–3, which changes the SBH and the Schottky to Ohmic transition condition. The results show that the CGO-based photodetector may get a responsivity of 0.371 and 5.570 A/W, respectively, for the Schottky and Ohmic modes.