衬底温度对PLD方法生长的ZnO薄膜结构和发光特性的影响

在不同的衬底温度下, 通过脉冲激光淀积的方法在Si衬底上生长出c轴高度取向的ZnO薄膜. ZnO薄膜的结构和表面形貌通过X射线衍射和原子力显微镜表征. 同时以He-Cd激光和同步辐射作为激发源来测试样品的发光特性. 实验结果表明, 在衬底温度为500℃时生长的ZnO薄膜具有非常好的晶体质量, 并且表现出很强的紫外发射. 在用同步辐射为激发源的低温(18K)光致发光谱中, 还观察到了一个位于430nm处的紫光发射, 我们认为这个紫光发射与存在于晶粒间界的界面势阱所引起的缺陷态有关, 这个势阱可能起源于Zn填隙(Zn _i)

Influence of Substrate Temperature on the Structure and Optical Properties of ZnO Thin Films Grown by Pulsed Laser Deposition

Highly c-axis oriented ZnO thin films were fabricated on Si(111) substrates at different substrate temperatures by pulsed laser deposition .X-ray diffraction and atom force microscope were employed to characterize the structure and surface morphology of the deposited ZnO films. The optical properties of the ZnO thin films were investigated by photoluminescence with He-Cd laser and synchrotron radiation as light source. The ZnO thin films grown at 500℃ show good crystallinity and intense UV emission. We also observed the violet emission centering about 430nm of ZnO films excited by synchrotron radiation at 18K. The violet luminescence is ascribed to the defects related to the interface traps existing at the grain boundaries, which probably originate from interstitial zinc(Zn i).