在较低温度(460℃)和无催化剂的条件下,通过热蒸发纯Zn粉在硅衬底上成功地制备出ZnO亚微米梳状结构.采用X射线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和室温光致发光光谱(PL)等技术分别研究了制备样品的晶体结构、表面形貌和光学性质.结果表明,具有均一直径和长度的单晶梳齿规则地生长在作为梳干的ZnO纳米片的Zn-(0001)极性面并沿[0001]方向择优生长.逆气流生长的样品的梳齿粗于顺气流生长样品的梳齿,而其波长为500 nm左右的绿色PL发射峰强度明显低于顺气流样品的发射峰强度,揭示出在氧气较充足的逆气流环境下生长的样品中的氧空位缺陷少于顺气流下生长的样品的氧空位缺陷.样品表面的Au纳米颗粒修饰大大增强了制备的梳状结构样品的紫外发射光强度,并明显降低了样品的绿色光致发射峰强度.
Comb-like ZnO sub-micrometer structures were successfully synthesized on Si(100) substrates though thermal evaporation of Zn power at a relatively low temperature(460 ℃) without any catalyst.The structures,morphologies and optical properties of ZnO samples were investigated by X-ray diffraction(XRD),field emission scanning electron microscopy(SEM),transmission electron microscope(TEM) and photoluminescence spectra(PL) at a room temperature.The results show that the synthesized ZnO has single crystal structure with comb-like morphology and the comb's teeth with uniform diameter and length has grown on Zn-(0001) polar surface of ZnO nanosheets.In addition,the teeth of the comb are thicker and longer,while PL green emission at 500 nm is weaker when they grow under the opposite flow direction compared with those samples growing in same flow direction for Zn vapor and working gas,revealing that the oxygen vacancy defects in the samples growing in the opposite flow direction are much lower than that in those growing in same flow direction.Room temperature photoluminescence spectra show that the ultraviolet emission of the sample is dramatically enhanced,while the green emission is declined after the surface modification of Au nanoparticles on ZnO sub-micrometer structures.