氧压对飞秒激光沉积ZnO/Si(100)薄膜光学性能的影响

利用飞秒脉冲激光沉积法在n-Si（100）单晶衬底上制备了ZnO薄膜, 分析了衬底温度、激光能量、氧压及退火处理对薄膜结构和光学性能的影响. X射线衍射结果表明, 当激光能量为15?mJ、氧压为10?mPa时, 80?℃生长的薄膜取向性最好. 场扫描电子显微镜结果显示薄膜的晶粒尺寸随激光能量的增加而减小、随衬底温度的升高而增大且退火后明显变大. 紫外-可见透射光谱显示薄膜具有90%以上的可见光透过率.光致发光谱表明当氧压为10 mPa时,除了ZnO的紫外本征峰外, 还有一波长为410 nm的强紫光峰, 当氧压增至20 mPa以上, 所有缺陷峰均消失, 只有376 nm处的紫外本征峰. 与纳秒激光法所制备的薄膜特性进行了比较, 结果表明, 虽然纳秒激光沉积所制备的薄膜具有更高的c轴取向度, 但飞秒激光沉积制备的薄膜具有更好的发光性能. 关键词： 氧化锌 飞秒脉冲激光沉积 透过率 光致发光

Effect of oxygen pressure on the optical properties of ZnO/Si(100) thin films deposited by femtosecond pulse laser

Zinc oxide （ZnO） thin films have been grown on n type Si （100） substrate using femtosecond pulsed laser deposition （PLD）. The effect of change in parameters, including substrate temperature, laser energy and oxygen pressure, on the structure and optical properties of ZnO films is discussed. The X ray diffraction results show that the ZnO films are highly c axis oriented when deposited at substrate temperature of 80?℃ with laser energy of 1\^5?mJ under oxygen pressure of 10 mPa. The field emission scanning electron microscopy indicates that the mean grain size increases with the increase of temperature, but decreases with the increase of laser energy. The ultraviolet visible transmissivity shows that the annealed films have a transmittance of 90% in visible rang. The photoluminescence spectra of ZnO films are discussed. In comparison, the structure and photoluminesceme properties of ZnO films produced by using nanosecond PLD are also studied.
Keywords： zinc oxide femtosecond pulse laser deposition transmissivity photoluminescence