分子束外延生长的极性与非极性BeZnO薄膜的比较研究

Abstract

BeZnO films were grown on different crystallographic planes( c-,a-and r-planes) of sapphire substrates using plasma-assisted molecular beam epitaxy( P-MBE). High quality BeZnO films were achieved using a multi-layer buffer design with full widths at half maximum( FWHMs) of rocking curves up to 600 arcsec. Polar BeZnO films were obtained on the a- and c-plane sapphire substrates,while the nonpolar ones were obtained on the r-plane sapphire substrate. The Raman spectroscopy confirmed the Be dopants in the ZnO were at the same level in three samples. The BeZnO sample grown on the r-sapphire substrate were found to have largest grains and higher FWHM, while the ones grown on a- and c-sapphire subatrates had the similar fine grains and lower FWHM. However,the photoluminescence( PL) spectra indicated the non-polar BeZnO sample had significantly stronger ultraviolet emission and weaker green emission than polar samples.