Optical properties of Al2O3 thin film deposited by pulsed laser deposition technique

An aluminum oxide (Al2O3) thin film has been grown on a quartz substrate by the pulsed laser deposition (PLD) technique at room temperature under a vacuum pressure of 10–2m bar at different laser wavelengths (1064 nm, 532 nm, and 355 nm). The optical properties concerning the absorption, transmission spectra, and energy gap were studied for the prepared thin film due to UV-visible spectrometer at room temperature with wavelength range (200-1000 nm). The absorption peak is 197 nm at wavelength 1064 nm, 196 nm at wavelength 532 nm, and 195 nm at wavelength 355 nm. The optical energy gap is an essential parameter for investigating thin films' properties. The value of the direct energy gap (Eg) for the prepared films was derived from the graph relationship between (ℎʋ h) and the energy gap (αhν)2 values for the various wavelengths (4.5 eV at 1064 nm, 5.1 eV at 532 nm, and 5.5 eV at 355nm), indicating the potential use of the thin film as gas sensors.