Surface and electrical characterizations of Ag/TiO2 and Ag/Ag-doped TiO2 nanoporous Schottky barrier diodes

Abstract

In this study, both structural and basic electrical characterizations (current-voltage) of Ag/TiO2 and Ag/Ag-doped TiO2 Schottky barrier diode were performed. Anodic oxidation (AO) was used to obtain the TiO2 layer and physical vapor deposition (PVD) and AO methods were used for Ag (silver) doping. Then, a group of coatings was heat treated at 450 degrees C to see the effect of the heat treatment and to make comparisons between samples. Ag (silver) rectifier contacts were deposited on the produced active layers and finally Ag/TiO2, Ag/TiO2 (annealed), Ag/Ag-doped TiO2 and Ag/Ag-doped TiO2 (annealed) Schottky barrier diodes were obtained. The I-V, semi-logarithmic I-V and double logarithmic I-V characterizations of the Schottky barrier diodes were investigated in depth and the effect of Ag doping and annealed was discussed in detail. With the effect of annealing, both pure TiO2 and Ag-doped TiO2-based Schottky barrier diodes rectification ratio values increased. This shows that the diode property improves after annealing. The diode ideality factor (n) values of Ag/TiO2, Ag/TiO2 (annealed), Ag/Ag-doped TiO2, and Ag/Ag-doped TiO2 (annealed) Schottky barrier diode are 1.27, 1.18, 1.07, and 2.58, barrier height (phi b\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\phi }_{b}$$\end{document}) values of those are 1.2 eV, 0.94 eV, 0.85 eV, and 0.93 eV, and saturation current (I0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${I}_{0}$$\end{document}) values of those are 1.21x10-14 A, 2.47x10-10 A, 9.77 x 10-9 A, and 3.47x10-10 A, respectively. TiO2 and Ag-doped TiO2-based diodes were found to be almost ideal diodes. Heat treatment reduced the ideality factor and barrier height in pure TiO2-based devices.