含纳米锗粒二氧化硅薄膜的光致发光研究

PHOTOLUMINESCENCE STUDY FOR NANOMETER Ge PARTICLES EMBEDDED Si OXIDE FILMS

以锗二氧化硅（ＧＳＯ）复合靶作为溅射靶，改变靶上锗与总靶面积比为０％，５％和１０％，用射频磁控溅射方法在ｐ型硅衬底上淀积了含锗量不同的三种二氧化硅薄膜．各样品分别在氮气氛中经过３００至９００℃不同温度的退火处理．通过对样品所作Ｒａｍａｎ散射光谱的分析，发现随着锗在溅射靶中面积比的增加，所制备的氧化硅薄膜中纳米锗粒的平均尺寸在增大．确定出随着退火温度由６００℃升高到９００℃，ＧＳＯ（５％）样品中纳米锗粒的平均直径由５４ｎｍ增至９５ｎｍ．含纳米锗粒大小不同的二氧化硅薄膜的光致发光谱中都存在位于２１ｅＶ的发光峰，它并不随纳米锗粒的存在与否或纳米锗粒的尺寸而改变，对于以纯二氧化硅靶制备的二氧化硅膜的光致发光谱中还多出两个位于１９和２３ｅＶ的发光峰．以上实验结果与量子限制模型的推论相矛盾，却可用量子限制／发光中心模型予以解释．

AbstractUsing a Ge SiO 2 (GSO) composite target with the Ge wafer in the target having percentage areas of 0%,5% and 10%,three types of nanometer Ge particles embedded Si oxide films were deposited on p type Si substrates by the rf magnetron sputtering technique. These samples were annealed in a N 2 atmosphere at 300,600,800 or 900℃ for 30min.From Raman scattering spectra,we obtained the sizes of nanometer Ge particles which increase with increasing percentage area of the Ge wafer in the sputtering target.From the fitting of Raman scattering spectra,average diameters of nanometer Ge particles in the GSO(5%) sample increase from 5 4 to 9 5nm with annealing temperature increasing from 600 to 900℃. The peak with energy around 2 1eV exists in the photoluminescence spectra of all the different sizes of nanometer Ge particles embedded silicon oxide samples.The photoluminescence spectrum of the silicon oxide film prepared using a pure SiO 2 target has other two peaks with light emission energies around 1 9 and 2 3eV respectively. The experimental facts are inconsistent with the predication of the quantum confinement model,but can be explained by the quantum confinement/luminescence center model.