直流磁控溅射ZnO薄膜的结构和室温PL谱研究

ZnO是一种新型的宽带化合化半导体材料 ,对短波长的光电子器件如UV探测器 ,LED和LD有着巨大的潜在应用。本实验研究采用直流反应磁控溅射法在硅衬底上沉积C轴择优取向的ZnO晶体薄膜 ,薄膜呈柱状结构 ,晶粒大小约为 10 0nm ,晶粒内为结晶性能完整的单晶 ,但晶粒在C轴方向存在较大的张应力。ZnO薄膜在He Cd激光器激发下有较强的紫外荧光发射 ,应力引起ZnO禁带宽度向长波方向移动 ,提高衬底温度有利于降低应力和抑制深能级的绿光发射

Structure and PL Spectrum of ZnO Films Prepared by DC Reactive Magnetron Sputtering

ZnO is a novel direct wide band semiconductor that has many potential applications in short wavelength optoelectronic devices such as UV detector, LED and LD. C axis oriented ZnO films were prepared by DC reactive magnetron sputtering on (100) Si substrate. ZnO films were composed of columnar crystallites with grain size about 100nm. TEM figure indicated that columnar crystallites were perfect single crystal insides, but there existed larger stress along grain boundary. ZnO films emitted UV photoluminescence (3 3eV) when excited by He Cd laser at room temperature. Stress at boundary caused intrinsic UV emission peak shift to lower energy. Oxygen vacancy or zinc interstitial caused deep level emission. Higher substrate temperature can improve the crystallinity and reduce stress and deep level green emission.