Investigation of the influence of the initial step of deposition on the properties of gallium nitride layer

Gallium nitride layers were deposited in Hydride Vapor Phase Epitaxy (HVPE) system on nitridated in various intervals sapphire substrates in order to evaluate the influence of time of ammonia surface treatment on the properties of the GaN layer. Applied intervals were 5, 10 and 15 minutes. Series of samples were investigated and results exhibit well recurrence. Morphology, crystalline properties, and optical quality were estimated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) imaging, High-Resolution X-ray Diffractmetry (HRXRD), and Photoluminescence (PL), transmission (T), and reflectance (R) measurements.