Sn掺杂ZnO纳米针的结构及其生长机制(英文)

Structure and Formation Mechanism of Sn-Doped ZnO Nanoneedles

利用包括磁控溅射和热氧化的两步法在Si(111)衬底上制备了Sn掺杂ZnO纳米针.首先用磁控溅射法在Si(111)衬底上制备Sn:Zn薄膜,然后在650℃的Ar气氛中对薄膜进行热氧化,制备出Sn掺杂ZnO纳米针.样品的结构、成分和光学性质采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、能量散射X射线(EDX)谱和光致发光(PL)光谱等技术手段进行分析.结果表明,制备的样品为具有六方纤锌矿结构的单晶Sn掺杂ZnO纳米针,Sn掺杂量为2.5%(x,原子比),底部和头部直径分别为200-500 nm和40 nm,长度为1-3μm,结晶质量较高.室温光致发光光谱显示紫外发光峰比纯ZnO的发光峰稍有蓝移,这可归因于能谱分析中探测到的Sn的影响.基于本实验的实际条件,简单探讨了Sn掺杂ZnO纳米针的生长机制.

We synthesized Sn-doped ZnO nanoneedles on Si（111） substrates in two steps： sputtering and thermal oxidation.First,a thin layer of the Sn∶Zn films was deposited onto the Si（111） substrates in a JCK-500A radio-frequency magnetron sputtering system.Sn-doped ZnO nanoneedles were then grown by simple thermal oxidation of the as-deposited films at 650 ℃ in Ar atmosphere.The structural,componential,and optical properties of the samples were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,high-resolution transmission electron microscopy（HRTEM）,energy dispersive X-ray（EDX） spectroscopy,and photoluminescence（PL） spectroscopy.The results reveal that the ZnO nanoneedles doped with 2.5%（x,atomic ratio） Sn are single crystalline with a wurtzite hexagonal structure.The lengths of the grown nanoneedles vary between 1 and 3 μm.The root diameters of the needles range between 200 and 500 nm while the tips have an average diameter of about 40 nm.Moreover,most of the Sn-doped ZnO nanoneedles are of high crystal quality.Room temperature PL spectroscopy shows a blue-shift from the bulk bandgap emission,which can be attributed to a Sn composition in the nanoneedles as detected by EDX.Based on the reaction conditions,the growth mechanism of the Sn-doped ZnO nanoneedles was also discussed.