Initial growth behaviors of GaN layers overgrown by HVPE on one-dimensional nanostructures

We developed a novel technique for obtaining a residual-strain-free GaN layer by the hydride vapor phase epitaxy (HVPE) method using one-dimensional nanostructures. The GaN layer was grown on a Si(1 1 1) substrate with a conventional AlN film and one-dimensional GaN nanostructures. The nanostructures were grown for 2 h with a HCl:NH3 gas flow ratio of 1:50. The growth rate of nanoneedles at 600 °C and nanorods at 650 °C were 2.553 and 2.193 μm/h, respectively. The overgrown GaN layer was grown at 1050 °C for 5 and 10 min. We obtained a GaN layer of 1.833 μm thickness and c = 5.1849 Å. The morphology, crystalline structure, and optical characteristics of the GaN layer were examined by field emission scanning electron microscopy, X-ray diffraction, and photoluminescence.