Role of oxygen pressure on the structural and photoluminescence properties of pulsed laser deposited GeO2 thin films

Role of oxygen pressure on the structural, optical and photoluminescence properties of GeO2 thin films grown by pulsed laser deposition has been investigated. X-ray diffraction reveals the hexagonal phase of GeO2 films. The lattice parameters of grown films are evaluated using Rietveld refinement. X-ray photoelectron spectroscopy results confirm the GeO2 formation. Rutherford backscattering spectrometry was used to determine the elemental composition and thickness of films. The optical transmittance of films increases from 85 to 93% and optical bandgap from 5.2 to 5.55eV with an increase in oxygen pressure from 100 to 200 mTorr. Strong PL emission around 396 nm is observed and the intensity of PL emission increases with increase in oxygen pressure from 100 to 300mTorr. Oxygen pressure of 200mTorr is found to be optimum for the growth of high-quality crystalline GeO2 thin films. The obtained PL results show the potential use of GeO2 thin films for optical applications.