生长温度对热蒸发法制备ZnO 纳米线的结构与发光性能影响

摘要

采用无金属催化剂的简单热蒸发法,在 Si (100)衬底上不同生长温度下成功地制备了高密度和大长径比的单晶 ZnO 纳米线。分别利用 X 射线衍射仪(XRD)、扫描电子显微镜(SEM-EDS)、透射电子显微镜(TEM)及荧光光谱仪表征样品的结构和发光性质。XRD和 TEM研究表明,所制备的样品为沿c 轴择优取向生长的单晶ZnO 纳米线,具有六方纤锌矿结构。SEM和TEM研究表明,生长温度对ZnO 纳米线的形貌及长径比的影响较大。当生长温度为700℃时,制备得到长径比为300(长度约为15μm,直径约为50nm)的 ZnO 纳米线；低于600℃时,形成花状 ZnO纳米锥或纳米棒；高于700℃时,形成小长径比的 ZnO纳米棒。此外,室温光致发光(PL)谱上出现一个强而尖锐的紫外发射峰以及一个弱而宽泛的蓝光发射峰。采用的热蒸发法制备ZnO 纳米线基于气-固(VS)生长机理且该生长方法可用于大规模、低成本制备高纯度的单晶ZnO 纳米材料。%The demonstrate that single crystal ZnO nanowires with high density and large length/diameter ratio are successfully grown on Si (100)substrates at a series of growth temperatures,via simple and catalyst-free thermal evaporation.The structural and photoluminescence properties of the resulting samples are characterized using X-ray diffraction (XRD),field-emission scanning electron microscope (FESEM),transmission electron microscope (TEM),and photoluminescence (PL),respectively.The XRD and TEM investigations indicate that the resulting ZnO nanowires are single crystalline grown along the c-axis direction in preference with the hexagonal wurtzite phase;SEM results show that the growth temperature has an effect on the morphology and the length/diameter ratio of the resulting ZnO nanowires.700℃ was believed to be the optimized growth tem-perature among the series of temperatures,and the ZnO nanowire of which possesses the largest length/diame-ter ratio estimated about 300 (15μm/50nm).Moreover,the room temperature PL measurements for the as-pre-pared ZnO nanowires exhibit two emission bands including a sharp and strong UV emission and a broad and week blue emission.The VS mechanism based deposition method in our experiment can be applied to large-scale manufacture of high-purity single crystal ZnO nanowires.