Dependence of The Structural and Optical Properties of Gallium Oxide Nanostructures on Laser Fluency

Abstract

In this research, thin films of gallium oxide β-Ga₂O₃ nanostructures were prepared by pulsed laser ablation in distilled water (PLAL), then deposited on quartz substrate by the drop-casting method at 90 ^oC. The Nd-YAG laser was used with a wavelength of 1064 nm and a repetition rate of 5 Hz. The effect of increasing laser fluencies on the structural and optical properties was investigated by, Transmission electron microscope (TEM), Atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer microscopy (UV-VIS). Crystallite size for all samples increased with the increasing the fluency of laser excepting at the fluency of laser 5.57 J/cm² was 9.78 nm. The formation of nanoparticles, spindle-like, nanosheet and core-shell of β-Ga₂O₃ have been observed by the images of TEM at the fluencies of laser 4.77, 5.57, 5.97, and 6.36 J/cm², respectively. The nanocluster and nanoroads of the β-Ga₂O₃ thin films can be seen by the SEM images at the all fluencies of laser 4.77, 5.97, 6.36 and 5.57 J/cm². The‏ ‏‎ results of XRD investigations showed‏ that the diffractions patern of β-Ga₂O₃ transformed from the monoclinic phase with (-201), ‎‎(-402), and (-603) into orthorhombic phase with (002), 004), and (006) when increased ‎the fluency of laser.‎‏‎ The energy bandgap decreased with the increase of laser fluencies, and the absorption peak was located in the UV region.