UHV/CVD自对准生长Ge量子点(英文)

在超高真空化学汽相淀积设备(UHV/CVD)上生长了小尺寸、大密度、垂直自对准的Ge量子点。采用原子力显微镜分析量子点的尺寸,可优化其生长温度和时间,在550℃,15s的条件下生长出尺寸最小的量子点,直径30nm,高约2nm。最上层多层结构Ge量子点中岛状量子点的比例为75%,其直径66nm,高11nm,密度4.5×109cm-2。利用透射电子显微镜分析了垂直自对准的Ge量子点的截面形貌,结果表明多层结构Ge量子点是垂直自对准的。Ge量子点及其浸润层的喇曼谱峰位分别为299cm-1和417cm-1,说明Ge量子点是应变的并且界面存在互混现象。采用光荧光谱分析了Ge量子点的光学特性。

Self-organized growth of Ge quantum dots by UHV/CVD

Small size, large density and vertical ordering Ge quantum dots (QDs) were grown by UHV/CVD system. AFM study was carried out to optimize growth temperature and time. The vertical ordering of the Ge QDs was investigated by transmission electron microscopy as well. The smallest Ge QDs were obtained at 550 ℃ for 15 s in our system, 30 nm in diameter and 2 nm in height. The stack Ge QDs were vertically aligned. About 75% of the uppermost Ge QDs are larger dome QDs, which is 66nm wide and 11nm high, with a density of 4.5×109cm-2. The Raman peaks are located at 299 cm-1 for Ge QDs and 417 cm-1 for wetting layer, which indicate the stacked Ge QDs are strained and wetting layers are intermixed. The optical characteristics of Ge QDs were studied by photoluminescence.