Effect of laser energy variation on the optical characteristics of GaN/Quartz thin films

Abstract

In this study, the pulsed laser deposition (PLD) technique was used to fabricate a GaN thin film. Ultraviolet-visible (UV-VIS) absorption spectra were used for testing the nanofilms. GaN thin films were produced on quartz substrates using pulsed Nd: YAG lasers with varied laser energies from 1200 mJ to 2000 mJ. Experimentally measured optical properties of the as-grown film include the optical transmittance spectrum; the optical transmittance value ranged between 62% and 84%, absorption behavior, energy gap determination, as well as the effects of laser pulse energy on these properties. A forward relationship was observed between the energy gap and thickness. It was noticed that the multi-optical energy bands of the grown GaN Nano film was tastes and calculated to have the values of 3.46, 3.35, 3.42, 3.61, and 3.64 eV, respectively. X-ray diffraction analysis showed that gallium nitride on porous silicon exhibits a polycrystalline and a cubic structure. Furthermore, a hexagonal structure was found under optimal conditions (0.532 micrometers, 1.6 J, 300 °C) with a high intensity peak and a high crystalline size at 2θ = 25.95°, 36.69°, 57.80°, and 63.75°, which correspond to the planes (200), (101), (110), and (103), respectively.