多孔氧化铝模板制备ZnS纳米线阵列及其光致发光谱

Optics Characteristic Research of ZnS Nanowire Arrays Prepared by Porous Anodic Aluminum Oxide Template

利用阳极氧化铝(AAO)模板,采用电化学沉积方法制备出了ZnS纳米线阵列。扫描电子显微镜(SEM)结果显示,AAO模板孔洞分布均匀,孔径基本一致(约50 nm),孔口呈六边形。TEM结果显示硫化锌纳米线的直径约50 nm(与AAM模板孔径一致),长度约为20μm(与AAM模板厚度一致)。电子衍射结果表明ZnS纳米线为多晶结构。比较了AAO模板组装ZnS纳米线阵列前后的光致发光谱,所得光谱显示,组装了ZnS纳米线阵列的模板的光致发光谱比没有组装的空模板相比多出两个发射峰,分别位于409,430 nm,且其发光强度随激发波长的增长而增强。解谱分析表明,这即为ZnS纳米线阵列的发光光谱的两个发射峰,是由导带与受主能级间的跃迁发光和施主与受主能级间的复合跃迁发光共同作用所致。发现由于纳米线尺寸的单一性,发射峰窄化明显,半峰全宽较小,这种现象在其他文献中未曾报道过。

Anodic aluminum oxide （AAO） template has a highly ordered nanoporous arrays with adjustable and controllable pore diameter ranging from 5 nm to 200 nm. AAO template formed by different method has different effort and use. The AAO template used in this article was formed by anodizing aluminum in the oxalic acid of 0.3 mol/L at 40 V and through two-step anodizing oxide method. The AAO template was used to synthesize ZnS nanowire arrays by the method of electrochemical deposition. The production can be proved to be ZnS nanowire arrays by transmission electron microscope electron diffraction image and energy dispersive X-ray spectrum. The TEM image shows that the diameter and length of the ZnS nanowires are about 50 nm and 20μm, respectively. The photoluminescence spectrum has a great contrast before and after having assembled ZnS nanowires. The photoluminescence spectrum display that the AAO template with ZnS nanowire arrays has two more emission peaks at 409 nm and 430 nm, and they are more intensive under the excitation with longer wavelength. There are different characters comparing with nanoparticles, nanorods and nanowires synthesized by other different methods. One is that the peak intensities are more strong if excitation wavelengths are more longer; the other is that the bandwidth is more narrow. To explain the origin of the ZnS nanowire arrays emission spectrum, the main reason is the transition caused from conduction band to accepter energy rank and from almsgiver energy rank to acceptor energy rank; the two types of luminescence act together so that ZnS nanowire arrays have two close emission peaks ; perhaps the other reason is the embellishment of ethanol. Else, the reason of narrow bandwidth is ZnS nanowire arrays have the uniform size distribution.