Pre-treatment effect of aqueous NH3 on conductivity enhancement and PL properties of GaN nanowires

Untreated and pre-treated with aqueous NH3, 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 (Nd) are calculated to be 8.54 × 1017 cm− 3 and 3.65 × 1018 cm− 3 whereas electron mobilities (μ) are 25 cm2/Vs and 86 cm2/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.

► GaN NWs untreated and pre-treated with aqueous NH3 have been synthesized.
► Nd found were 8.54 × 1017 cm− 3 and 3.65 × 1018 cm− 3 for untreated and pre-treated NWs.
► μ measured were 25 cm2/Vs and 86 cm2/Vs for untreated and pre-treated GaN NWs.
► Single and strong PL emission peak at 370 nm was measured for pre-treated NWs.
► Untreated NWs showed relatively weak PL at 370 nm with a shoulder peak at 462 nm.