中文摘要：

以n型单晶Si（111）为衬底,利用Au作为催化剂,在温度、N2流量和生长时间分别为1 100℃,1.5L·min-1和60min的条件下,基于固-液-固生长机制,生长了直径为6080nm、长度为数十微米的高密度Si纳米线。随后,以Y2O3粉末为掺杂源,采用高温扩散方法对Si纳米线进行了钇（Y）掺杂。利用扫描电子显微镜、X射线衍射仪和荧光分光光度计对不同掺杂温度（9001 200℃）、掺杂时间（1560min）和N2流量（0400sccm）等工艺条件下制备的Y掺杂Si纳米线的形貌、成分、结晶取向以及激发光谱和发射光谱特性进行了详细的测量和表征。结果表明,在掺杂温度为1 100℃,N2流量为200sccm、掺杂时间为30min和激发波长为214nm时,Y掺杂Si纳米线样品表现出较好的发光特性。样品分别在470500和560600nm范围内出现了两条发光谱带。560600nm的发光带由两个发光峰组成,峰位分别为573.6和583.8nm,通过结构分析可以推测,这两个发光峰是由Y3＋在Si纳米线的带隙中引入的杂质能级引起的。而470500nm较宽的发光带同样来源于Y离子在Si纳米线带隙中引入的与非晶SiOx壳层中氧空位能级十分接近的杂质能级。

英文摘要：

High-density silicon nanowires were grown on the n-（111）single crystal silicon wafer based on solid-liquid-solid mechanism using Au films as catalyst.Then silicon nanowires were doped with yttrium（Y）with high temperature diffusion method using Y2O3 powder as doping source.The experimental parameters were doping temperature of 9001 100 ℃,doping time of 1560min and N2 flow rate of 0400sccm.The morphology of nanowires was measured with scan electron microscopy（SEM）.The composition and crystalline orientation of nanowires were analyzed with X-ray diffraction（XRD）.The measurement and characterization of excitation and emission spectrum of silicon nanowires were carried out with F-4600 fluorescence spectrophotometer.The SEM images show that the curved,winding silicon nanowires with uniformly size and high density were grown on the surface of silicon wafer.The average diameter and length of silicon nanowires are about 100 nm and several tens of microns,respectively.The photoluminescence spectra of undoped silicon nanowires were measured with an excitation wavelength of 214 nm at room temperature,which exhibits a broad blue emission in the range of 450480nm with the center peak of 470 nm.The blue emission band is derived from the oxygen vacancies in the amorphous SiOxshell of the Si nanowires.Also,the photoluminescence spectra of Y doped silicon nanowires were measured,which consists of a broad blue emission band in the range of 470500nm with the center peak located near the 488 nm and a narrow yellow-green luminescence band in the range of560600nm with two emission peaks of 573.6and 583.8nm.The experimental results show that with the increase of doping temperature from 900 to 1 200 ℃,the strength of the yellow-green light emission band has experienced increase firstly and then decrease,the maximum value appears at 1 100 ℃.In addition to the temperature,a similar phenomenon was also observed by changing the doping time and nitrogen flow.The yellow-green luminescence intensity of Y doped silicon nano