Optimization of the key parameter V/III ratio in AlN thin film growth on patterned sapphire

Abstract Aluminum nitride (AlN) thin films, widely used in UV–VIS applications, were grown on patterned sapphire substrates using different V/III ratios. The study aimed to investigate the effects of low and high V/III ratios on the structural quality, optical properties, and growth mode of the AlN films. The low and high V/III ratios were set at 590 and 1180, respectively. Optical properties were analyzed using UV–Vis–NIR spectrophotometry, while surface morphologies and crystal structures were characterized with scanning electron microscopy (SEM) and high-resolution X-ray diffraction (HR-XRD). The results showed that films grown with the higher V/III ratio exhibited improved crystal quality, as evidenced by narrower FWHM values in XRD measurements and increased total and diffuse reflectance, both of which reflect smoother surfaces and better optical properties. Conversely, films grown with the lower V/III ratio showed more lateral growth and increased surface roughness. These findings provide insights into optimizing growth parameters for high-quality AlN films, essential for advanced optoelectronic applications.