Electrical, Optical, and Structural Characteristics of Sn-Doped ZnO Thin Films for Schottky Diodes Applications

This research involved the creation of undoped and 3% Sn-doped ZnO thin films on glass and silicon substrates using RF magnetron co-sputtering. A thorough analysis of the structural and optical properties of the samples on glass substrates was performed. The X-ray diffraction (XRD) results showed that the films had a hexagonal wurtzite structure, with a clear (002) preferred orientation. The band gap energies were determined from photoluminescence spectra. In addition, the optical transmittance spectrum of the films were determined using a UV–Visible spectrophotometer. The electrical characteristics of the Au/ZnO/n-Si and Au/ZnO:Sn (3%)/n-Si structures were evaluated at room temperature through current–voltage measurements. The results demonstrated that Sn deposition increased the barrier height and improved the diode performance by reducing the series resistance. Furthermore, the capacitance and conductance characteristics of the Au/ZnO:Sn (3%)/n-Si structure were analyzed over the frequency range of 50 kHz to 1 MHz under an applied bias of ±4 V using C–V and G/ω–V measurements. The findings from capacitance–voltage, capacitance–frequency, conductance–voltage, and conductance–frequency analyses indicated that Sn doping expanded the depletion region and reduced scattering effects associated with interface states.