利用Si(111)衬底,以Au-Al为金属催化剂,基于固-液-固生长机理,在温度为1100◦C, N2气流量为1.5 L/min、生长时间为30—90 min等工艺条件下,制备了直径约为100 nm、长度为数微米的高密度、均匀分布、大面积的Si纳米线(∼1010 cm−2).对Si纳米线进行了Eu掺杂,实验研究了不同长度的Si纳米线以及不同掺杂温度、掺杂时间等工艺参数对Eu 离子红光发射的影响,利用扫描电子显微镜和X射线衍射仪对Si纳米线表面形貌和Eu掺杂后Si 纳米线的结晶取向进行了测量和表征；室温下利用Hitachi F-4600型荧光分光光度计对样品的激发光谱和发射光谱进行了测试和分析.结果表明：在Si纳米线生长时间为30 min、掺杂温度为1000◦C、最佳激发波长为395 nm时,样品最强荧光波长为619 nm (5D0→7F2)；同时,还出现了576 nm (5D0→7F0),596 nm (5D0→7F1),658 nm (5D0→7F3)和708 nm (5D0→7F4)四条谱带.%High-density (∼1010 cm−2) silicon nanowires are grown directly from n-(111) single crystal silicon based on solid-liquid-solid mechanism by using Au-Al films as metallic catalyst. The results indicate that the optimal parameters to realize Si nanowires with high density and uniform distribution are as follows. The thickness of Au-Al film is between 5 and 15 nm, the temperature is 1100 ◦C, and the flow of N2 is 1.5 L/min. The diameters and lengths of the formed Si nanowires are 100 nm and from several micrometers to sereral tens of micrometerss, respectively. Then Eu-doped Si nanowires are studied. The influences of the different lengths of Si nanowires, doping temperature (900–1100 ◦C), and doping time (15–60 min) on the luminescence of Eu3+are experimentally investigated. The morphologies and microstructures of the SiNWs, the photoluminescence properties and growth crystall orientations are characterized and analyzed by the scanning electron microscopy, the Hitachi F-4600 fluorescence spectrophotometer and X-ray powder diffraction. The results show that the Eu-doped Si nanowires have a stronly red luminescencent with an emission peak position at 619 nm (5D0 →7F2) when the doping temperature is 1000 ◦C, the grow time of SiNWs is 30 min, and the optimal excitation wavelength is 395 nm. At the same time, there are four emission bands of 576 nm (5D0 →7F0), 596 nm (5D0 →7F1), 658 nm (5D0 →7F3), and 708 nm (5D0 →7F4) that are observed. Compared with the scenario of the silicon substrate, the Eu-doped Si nanowires present strong red light emission. The photoluminescence properties of Eu-doped Si nanowires have potential applications in the lighting and the silicon optoelectronic integration. However, the parameters of Si nanowires such as diameter, density, surface morphology have great influences on the photoluminescence properties of Eu-doped Si nanowires, which are necessary to be further studied.
展开▼
