Electrical characterization of Au/ZnO/TiO2/n-Si and (Ni/Au)/ZnO/TiO2/n-Si Schottky diodes by using current-voltage measurements

Abstract

In this study, we fabricated two types Schottky diodes (SDs), Au/ZnO/TiO2/n-Si (MIS-1) and (Ni/Au)/ZnO/TiO2/n-Si (MIS-2), to investigate main electrical parameters such as ideality factor (n), barrier height (Phi(b)), interface states (N-ss) and series resistance (R-s). ZnO/TiO2 thin film was deposited on polycrystalline n-type Si substrate using DC magnetron sputtering system. The analysis of current-voltage (I-V) measurements of ZnO/TiO2/n-Si Schottky diodes (SDs) were performed with two different rectifier contacts as Au and Ni/Au at room temperature. The values of n, Phi(b) and R-s were calculated as 1.80, 0.88 eV and 106.12 Omega for MIS-1 and 1.97, 0.82 eV and 50.13 Omega for MIS-2 SDs, respectively, from forward-bias I-V curves. The energy distribution profile of Nss for both SDs was obtained from the forward bias I-V measurements by taking the bias dependence of the effective barrier height (Phi(e)) into account. In addition, the values of Phi(b) and R-s of MIS-1 and MIS-2 SDs were determined using Cheung's and Norde's functions and the obtained results have been compared with each other.