Growth of nano- and microstructured GaN in bulk powder and on substrate

✍ Scribed by Ghosh, R. ;Basak, D.

• Book ID: 105364409
• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 504 KB
• Volume: 204
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200723012

✦ Synopsis

Abstract

A detailed investigation has been carried out to study the effects of growth temperature, NH~3~ flow rate, grinding‐mediated annealing of the as‐synthesized GaN powder, different substrates and Au catalyst on the products grown by a direct reaction of Ga with NH~3~. Nanowires of diameter in the range 15–40 nm are grown around a narrow temperature zone, 1000 °C < t < 1100 °C, with a 150 sccm NH~3~ gas flow rate. Beyond this temperature zone, GaN platelets are formed in a large scale. Annealing of the as‐synthesized GaN powder at 800 °C after a grinding process results in the growth of dendrite‐like GaN nanostructures and above 800 °C, only hillocks of GaN platelets are grown. The layers formed on sapphire and ZnO/quartz substrates consist of GaN nano‐ and microrods of diameter 40–100 nm and 1–1.5 μm respectively that show ultraviolet (UV) emission peaks below 400 nm. Large‐scale synthesis of GaN nanorods of diameter 60–100 nm has been achieved on Au/quartz substrate at 1050 °C with a 150 sccm of NH~3~ gas flow rate. The nanorods exhibit a strong UV emission peak indicating a better optical quality. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)