Cu catalyst assisted growth of GaN nanowires on sapphire substrate for p-type behavior

Copper catalyst assisted growth of GaN nanowires (NWs) on c-plane sapphire substrate has been investigated using Chemical Vapor Deposition Method. The impact of different reaction temperatures on the crystallinity have been studied by high resolution X-ray diffraction and Raman spectroscopy. The results has confirmed that the crystalline structure of GaN NWs are wurtzite. The surface morphology of the GaN nanowires have been analysed by scanning electron microscopy. The transmission electron microscopy (TEM) analysis reveals that the grown nanowires are single crystalline in nature. The diameter of NW decreases gradually from 1 μm to 65 nm and length is ∼7 μm. Composition and impurities in GaN NWs have been studied by EDX analysis. The resistivity (ρ = 5 × 101 Ω cm), hole mobility (μp = 2.97 cm2/V s) and hole concentration (p = 4.17 × 1016 cm−3) of GaN nanowires have been estimated by Hall measurement. Room temperature photoluminescence study shows that the near band edge emission of GaN NWs was red shifted to 3.26 eV.