Optical Properties of Wurtzite-and Zincblende-GaN Films Grown by RF Plasma-MBE

Abstract

Both wurtzite-and zincblende-GaN films have been grown on sapphire and MgO substrates, respectively, and examined by photoluminescence and x-ray analysis. GaN films were grown on suitably prepared Al2O3 and MgO substrates by molecular beam epitaxy employing a rf plasma discharge, nitrogen free radical source. The wurtzite-and zincblende-GaN films exhibited dominant near band-edge emission, the nature of which will be compared and contrasted for both phases in this paper. X-ray diffraction data for both phases will also be discussed.

Raman spectroscopy study on free-standing GaN separated from sapphire substrates by 532 nm Nd:YAG laser lift-off

“…We use a pulsed Nd:YAG laser with longer wavelength (532nm) for performing the lift-off of a GaN films (5.8pm thick) from sapphire. Although the 2.33eV (532nm) radiation is below the absorption edge of GaN (3.41eV) [7], the radiation can be absorbed by free carriers. The absorption coefficient depends on the concentration of electron-hole pairs [8,9].…”