在c-面蓝宝石上控制生长高质量的ZnO单晶薄膜

摘要

High quality ZnO thin film was obtained on c-sapphire substrate by using a technique of plasma assisted molecular beam epitaxy ( P-MBE ) , in which MgO and low temperature ZnO are used as buffer layers. High-resolution XRD measurement shows the full width at half maximum (FWHM) of (002) and (102) are only 68. 4 and 1 150 arcsec, respectively. In the meantime, atomically smooth surface with root mean square (RMS) surface roughness of 0. 842 nm is realized. In addition, Raman and photoluminescence ( PL) measurements show that ZnO layer has extremely low stress level and defect density. The realization of high quality ZnO thin film pays a good way for the application of ZnO-based optoelectronic devices.%利用MgO和低温ZnO的缓冲层技术,在c面蓝宝石衬底上用等离子体辅助分子束外延( P-MBE)的方法生长了高质量的ZnO单晶薄膜。通过XRD测试,ZnO薄膜样品具有c轴方向的择优取向,其(002)方向摇摆曲线的半高宽(FWHM)仅为68.4 arcsec,(102)方向摇摆曲线的半高宽(FWHM)为1150 arcsec,显示了外延薄膜极高的晶体质量。另外从扫描电子显微测试结果和原子力显微测试结果来看,ZnO薄膜具有极为平整的表面,3μm ×3μm面积内的均方根粗糙度仅为0.842 nm,接近原子级的平整。拉曼光谱( Raman)和荧光光谱( PL)测试结果显示,ZnO薄膜样品内部的应力基本释放,而且具有极低的点缺陷密度。高质量ZnO单晶薄膜的实现为ZnO基的光电器件的制备提供了坚实的基础。