Pre-treatment effect of aqueous NH ₃ on conductivity enhancement and PL properties of GaN nanowires

Untreated and pre-treated with aqueous NH ₃, GaN nanowires have been synthesized by nickel assisted CVD method at 1050 °C. The effect of pre-treating has been studied on the morphology, electrical and optical properties of the as-grown NWs. The resistivities of untreated and pre-treated NWs are calculated to be 40.5 ω-cm and 2.85 ω-cm respectively, which demonstrate that the conductivity of the pre-treated NWs has been enhanced significantly. The carrier concentrations (N _d) are calculated to be 8.54 × 10 ¹⁷ cm ^{- 3} and 3.65 × 10 ¹⁸ cm ^{- 3} whereas electron mobilities (μ) are 25 cm ²/Vs and 86 cm ²/Vs for untreated and pre-treated NWs respectively. Due to dramatic increase in the carrier concentrations and mobilities, these pre-treated GaN NWs are potentially applicable in low voltage and nano-scale electronics devices fabrications. Room temperature photoluminescence (PL) measurements of pre-treated NWs show a strong near-band-edge emission at 370 nm (3.35 eV) without blue and yellow emission indicating good optical quality of the NWs which have also potential application in optoelectronics and LEDs.