Optical and electrical properties of E-Beam deposited TiO2/Si thin films

Abstract

In this paper, optical and electrical properties of E-Beam deposited TiO2/Si thin films have been studied and investigated extensively. The films were deposited on p-type (100) silicon wafer by using electron beam evaporation technique. The thickness of the thin films was measured by a spectroscopic reflectometer, which is about 216 nm. The fabricated titanium oxide (TiO2) thin films were annealed at 800 °C for 1 h under N2 ambient. X-ray diffraction measurements were performed to study the structure and phase identification of the fabricated TiO2 thin films. For the optical properties, reflection, transmittance, refractive index and absorption coefficient were obtained and analyzed. The photocurrent and dark current of the fabricated films were measured by I–V measurements. The measurement of the current–voltage (I–V) characteristics possesses good ohmic contact. The electrical characterizations of the films were performed in the range of the low frequencies (50 and 100 kHz) and high frequencies (750 kHz and 1 MHz) by the capacitance–voltage and conductance–voltage measurements at room temperature. The capacitance of the fabricated TiO2 MOS capacitor at both high and low frequencies increases with the decrease in frequencies. The obtained conductance curves (peaks) increase with the decreasing in the frequencies. This can be due to the interface state density, series resistance and interfacial dielectric of the fabricated MOS capacitors. The variation in the characteristics of the fabricated film shows that TiO2 is a promising candidate to be used in the optoelectronic and future UV detector applications as a switch, such as an optical amplifier, emitter, and UV light detectors.