Structural, Morphological, and Optical Characterization of GaN/p-Si Thin Films for Various Argon Flow Rates

Abstract

A thin film of gallium nitride (GaN) was successfully grown onto p-Si by a radio-frequency (RF) magnetron sputter for different argon flows. X-ray diffraction (XRD) results proved that GaN thin film had a polycrystalline structure with planes of (100) and (110). Structural parameters (grain size, crystal quality, and texture coefficient) of the thin film were changed by the argon flows. The reasons for these changes are discussed in detail. Raman measurements showed the corresponding characteristic $$ E_{2} \left( {\text{high}} \right) $$ peak of the hexagonal GaN and showed that all the materials have a compressive stress, in compliance with the XRD. Atomic force microscopy images presented periodic grain arrangements with almost homogeneous, nano-structured GaN thin film surface. Scanning electron microscopy of the thin film showed an almost homogeneous, granular structure with some agglomerations due to the van der Waals interactions between particles. Optical analysis shows that changing the argon flows slightly altered the material’s optical band gap energy.