Tb掺杂Si纳米线的光致发光特性

Study on the Photoluminescence Properties of Tb Doped Si Nanowires

以金属Au-Al为催化剂,在温度为1 100℃,N_2气流量为1 500 sccm、生长时间为30 min,从Si(100)衬底上直接生长了直径约为50~120 nm、长度为数百纳米的高密度、大面积的Si纳米线。然后,利用Tb_2O_3在不同温度(1 000~1 200℃)、掺杂时间(30~90 min)和N_2气流量(0~1 000 sccm)等工艺条件下对Si纳米线进行了Tb掺杂。最后,对Si(100)衬底进行了Tb掺杂对比。室温下,利用荧光分光光度计(Hita—chi F-4600)测试了Tb掺杂Si纳米线的光致发光特性。实验研究了不同掺杂工艺参数(温度、时间和N_2气流量)对Tb^(3+)绿光发射的影响。根据Tb^(3+)能级结构和跃迁特性对样品的发射光谱进行了分析。结果表明,在温度为1 100℃,N_2气流量为1 500 sccm、时间为30 min等条件下制备的Si纳米线为掺杂基质,Tb掺杂温度为1 100℃,N_2气流量为1 000 sccm、光激发波长为243 nm时,获得了最强荧光发射,其波长为554nm(~5D_4→~7F_5),同时还出现强度相对较弱的494 nm(~5D_4→~7F_6),593 nm(~5D_4→~7F_4)和628 nm(~5D_4→~7F_3)三条谱带。Tb掺杂的体Si衬底在波长554 nm处仅有极其微弱的光致发光峰。

Silicon nanowires with high density ,uniform distribution and large area were produced directly from Si （100） based on solid-liquid-solid mechanism under the growth temperature of 1 100 ℃ with 30 min .The flow of N2 is 1 500 sccm and Au-Al films is used as metallic catalyst .The diameters of Si nanowires is 50~120 nm and the lengths of the formed Si nanowires is hundreds of nanometers .After that Tb-doped Si nanowires were reserched .We experimentally investigated the influences of the different process parameters on the luminescence of Tb-doped Si nanowires .The main process parameters includ doping tempera-ture（1 000~1 200 ℃） ,doping time （30~90 min） and gas flow rate of N2 （0~1 000 sccm） .Finally ,Tb-doped bulk silicon sub-strates have been studied experimentally . We characterized and analyzed the photoluminescence properties of Tb-doped Si nanowires with the Hitachi F-4600 fluorescence spectrophotometer .The corresponding relation of energy level structure and transition properties of Tb ion with the experimental spectrum is analyzed in detail .The experiment result indicates that the Tb-doped Si nanowires have a stronly green luminescencent .The emission peak position of the largest intensity at 554 nm （^5 D4 →^7 F5 ） with the doping temperature 1 100 ℃ ,the flow of N2 1 000 sccm and the excitation wavelength 243 nm .At the same time , three emission bands of 494 nm （^5 D4 → ^7 F6 ） ,593 nm （^5 D4 → ^7 F4 ） and 628 nm （^5 D4 → ^7 F3 ） were observed under room tempera-ture .The Tb-doped Si nanowires appeared strong green light emission compared with the bulk silicon substrate .Its application has a certain reference value for studying the characteristics of luminescence of rare earth element doped Si based material .Mean-while ,the photoluminescence properties of Tb-doped Si nanowires affected by the diameter ,length ,distribution and density of Si nanowires .That is necessary forour further research .