From Nanoparticles to Nanowires of GaN with Different Hydrogen Gas Flow Rates by PDC-PECVD

Abstract

III-V family semiconductors have received considerable attention for microelectronic and optoelectronic applications. In particular, GaN nanostructures have a huge number of applications due to its wide and direct band gap, high melting point and high electrical breakdown field. Wurtzite structure of GaN nanoparticles and nanowires were synthesized using different hydrogen gas flow rate of 0, 3 and 7sccm (standard cubic centimetres per minute) via pulsed direct current plasma enhanced chemical vapor deposition (PDC-PECVD) at low temperature, 650°C. GaN nanostructures including nanowires and nanoparticles were grown using gallium atoms and nitrogen plasma on Si (111) substrates. Characterizations of GaN nanostructures were carried out using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field emission electron microscopy (FE-SEM). Morphology of the grown GaN nanostructures changed from nanoparticles to nanowires with increasing the hydrogen gas flow rates. XRD results demonstrate that lattice constants ratio of a/c of hexagonal structure and gallium/nitrogen ratio in the synthesized GaN nanostructures decreased with increasing hydrogen flow rates. GaN nanoparticles and nanowires were grown on Si (111) with average diameters of 45nm and 25nm, respectively. The results show that the hydrogen plasma can significantly affects on morphology and lattice parameters of GaN nanostructures by low temperature PECVD method.