论文部分内容阅读
以Au薄膜为催化剂、ZnO与碳混合粉末为反应源,采用碳热还原法在单晶Si衬底上制备了ZnO纳米线阵列。通过扫描电子显微镜(SEM)、X射线衍射仪(XRD)、荧光分光光度计对样品的表征,研究了反应源温度对ZnO纳米线阵列的定向性和光致发光性能的影响。样品在源温度920℃条件下沿(002)方向择优生长,定向性最好,温度过低不利于ZnO纳米线阵列密集生长,而温度过高导致Zn原子二次蒸发,因而也不利于纳米线阵列的定向和择优生长;样品在源温度880℃有最强的近紫外带边发射,表明温度过高和过低都不利于ZnO晶体结构的优化;由于ZnO纳米线在缺氧氛围下生长,氧空位是缺陷存在的主要形式,因此所有样品都有较强的绿光发射。温度升高导致纳米线生长速度提高而增加了氧空位缺陷数量,从而使样品绿峰强度增强并在源温度920℃时达最大值,但温度的进一步升高可导致ZnO纳米线表面Zn元素的蒸发而降低氧空位缺陷的数量,从而抑制绿峰强度。
Using Au thin film as catalyst and mixed ZnO and carbon powder as reaction source, ZnO nanowire arrays were prepared on single crystal Si substrate by carbothermal reduction method. The effects of reaction temperature on the orientation and photoluminescence of ZnO nanowire arrays were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and fluorescence spectrophotometer. The sample grows preferentially along the (002) direction at a source temperature of 920 ° C, with the best orientation. The too low temperature is not conducive to the dense growth of the ZnO nanowire arrays. However, the high temperature leads to the secondary evaporation of the Zn atoms and thus to the nanowires The orientation and preferred growth of the array were observed. The strongest near-UV band edge emission was observed at 880 ℃ for the sample, indicating that the temperature is too high and too low to optimize the ZnO crystal structure. Due to the growth of ZnO nanowires under anoxic conditions, Oxygen vacancies are the predominant form of defects, so all samples have a strong green emission. The increase of the temperature leads to the increase of the growth rate of the nanowires and the increase of the number of oxygen vacancies. As a result, the green peak intensity of the sample increases and reaches the maximum at the source temperature of 920 ° C. However, the further increase of the temperature leads to the increase of Zn element Evaporation and reduce the number of oxygen vacancies, thereby inhibiting the green peak intensity.