Ce掺杂Si纳米线的制备及其蓝光发射特性

以抛光和“金字塔”织构表面的单晶Si(100)为衬底，分别以Au和Au-Al为金属催化剂，在温度为1 100 ℃、N₂气流量为1 500 sccm、生长时间为15～60 min等工艺条件下，制备了直径约为50～200 nm、长度为数微米至数十微米和不同分布的Si纳米线。然后，利用CeO₂粉末为掺杂剂，在温度为1 100～1 200 ℃、N₂流量为1 000 sccm、掺杂时间为30～60 min等工艺条件下对Si纳米线进行Ce掺杂。实验研究了不同Si纳米线长度、密度和分布等对Ce3+蓝光发射的影响。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，同时利用FLS920全功能型荧光光谱仪对样品的荧光量子效率进行了测试。结果表明，在Si纳米线生长时间为30 min、织构表面和密度相对较低时以及最佳激发光波长为328 nm时，样品发射光波长为405 nm(5d→2F_5/2)荧光强度较大，实现了强的蓝光发射，其荧光量子效率达到了65.57%。通过光谱功率分布和CIE-1931标准公式进行计算，Ce掺杂Si纳米线样品的色坐标为(0.16, 0.03)；发光强度大，量子效率高使其在照明、显示等领域有着潜在的应用价值，同时对Si纳米线在发光领域的研究和应用具有一定的参考价值。

The Preparation and Blue Light Emission Characteristic of Ce-Doped Si Nanowires

Si nanowires were prepared from the Si (100) single with polishing and “pyramid” texture surface. The process conditionswere as follows: the growth temperature was 1 100 ℃, N₂ gas flow rate 1 500 sccm, growth time 15~60 min, and Au and Au-Al were used metal catalyst, respectively. The diameters of the formed Si nanowires are 50~200 nm and the length were from several micrometers to sereral tens of micrometers. Then, Ce-doped Si nanowires were prepared under the temperature of 1 100~1 200 ℃, 1 000 sccm of N₂ flow rate, 30~60 min of doping time and CeO₂ powder as doping agent. The influences of the different length, density and distribution of Si nanowires on the luminescence of Ce3+ were experimentally investigated. The photoluminescence properties and fluorescence quantum efficiency were test ed and analyzed by the Hitachi F-4600 fluorescence spectrophotometer and the FLS-920 full functional fluorescence spectrometer under room temperature. The results showed that the Ce-doped Si nanowires had a stronly blue luminescencent with an emission peak position at 405 nm(5d→2F_5/2) and the full width at half maximum was 36.7 nm when the grow time of Si nanowires was 30min, the surface was “pyramid” texturewith lower density and the optimized excitation wavelength was 328 nm.Compared with the silicon substrate,the Ce-doped Si nanowires appeared strong blue light emission. The fluorescence quantum efficiency reached 65.57%. The color coordinates of Ce-doped Si nanowires was (0.16, 0.16) based on the distribution of emission spectral and CIE-1931 standard formula. Ce-doped Si nanowires have potential applications in the areas of lighting and display because of its strong luminous intensity and relatively high fluorescence quantum efficiency. At the same time this paper has a certain referential value in the field of research and application of Si nanowires.