纳米硅的拉曼散射和可见光致发光

我们用射频共溅射技术和后退火处理,获得在石英、Si和Ge衬底上的纳米晶Si(nc-Si) Raman测量清楚地显示出nc-Si的类Lo模(～518cm-1)和类To模(～814cm-1),Raman峰的半高宽(FWHM)和积分强度也显示随退火温度Ta增加的变化,这一结果同nc-Ge/SiO2的情况类同,退火温度Ta=650℃时,nc-Si的平均尺寸为4.9nm 我们用514.5nm的Ar+激光激发,得到了室温可见PL,结果表明:PL谱在2.2eV处有一强的发光峰,与nc-Ge/SiO2相比,SiO2中nc-Si的PL峰更强,峰值能量较大,相应的Ta也较高,当Ta>800℃和Ta<600℃时,PL峰很弱 通过地研究膜中nc-Si的含量与PL峰之间的关系,表明nc-Si的含量对PL峰的积分强度有重要影响,对峰位影响不大,当Si/SiO2靶面积比为1∶1时,PL峰最强

Raman Scattering and Visille Ploto luminescence from Nanocrystallites Si

In this work, we employed rf co-sputtering technique and post-annealing treatment to embed nanocrystallite Si (nc-Si) into SiO2 thin f ilms deposited on glass substrates and Si. Ge wafers. Ramma measurements revel c lear LO-like mode (at 518cm-1) and TO-like mode (at 814.5cm-1) from nc-Si. The FWHM and the integral intensity of Ramma scattering peaks exhibit a pronounced change with increasing annealing temperature. Ramma measurements indi cate that samples annealed at 650℃ have a 4.9nm average nc-Si size. We perform ed room visible PL measurements for the samples with 514.5nm Ar ion laser radiat ion at room temperature. The results showed that for he samples annealed at 650 ℃, there is a strong peak appearing at about 2.2eV in PL spectra, By comparison with the corresponding value of nc-Ge in SiO2 films, it is found that PL peak energy of nc-Si in SiO2 is larger and the corresponding annealing temperatur e is higher, When annealing temperature is higher than 800℃ and lower than 600 ℃, the PL peak is very weak, We also investigated the correlation between the n c-Si content in films and the PL peaks , the result shows that the content of nc -Si has important influence on the peak integral intensity but little on the pea k position, In our experiment, the PL peak is the strongest when the ratio of S i and SiO2 targets area is 1∶1.