Controlled synthesis of GaN square shape nanorods: Their excellent electronic and optical properties for optoelectronics applications

High quality square shaped GaN nano-rods are successfully synthesized by a novel method of precursors pretreatment with aqueous NH3 via CVD method at 1300 degrees C. The pre-treatment effect significantly enhanced the conductivities, carrier concentrations and mobilities in GaN nanorods. GaN nanowires have also been synthesized at 1300 degrees C without treating precursors with aqueous NH3. Diameter of the nanorods and nanowires are measured in the range of 100-200 nm whereas length is in tenth of microns. Room temperature PL analysis of GaN nanowires displayed a high intensity near-band-edge emission at 370 nm with week blue emission. The GaN square nanorods exhibited the yellow band emission at 565 nm vanishing the weak blue emission along with the near-band-edge emission at 369 nm indicating their potential applications in optoelectronics. The carrier concentrations (Nd) are calculated to be 3.65-5.25 x 10(16) cm(-3) and 2.25 similar to 5.88 x 1018 cm(-3) for nanowires and nanorods respectively. The electron mobilities (mu) calculated for the GaN nanowires were in the range of 200 similar to 300 cm(2)/Vs where as for the nanorods were 154 similar to 625 cm(2)/Vs. The high quality GaN nanorods building blocks with high conductivities, career densities and mobilities will be a tremendous breakthrough in low voltage operating nano-devices.

Automated summary

High quality square shaped GaN nano-rods were synthesized via CVD method with pretreatment of aqueous NH3, leading to enhanced conductivities, carrier concentrations and mobilities. GaN nanowires were also synthesized without the pretreatment. The research indicates the potential application of GaN square nanorods in optoelectronics.