Highly tensile-strained Ge quantum dots on GaSb by MBE for light sources on Si

doi:10.1109/PHOSST.2016.7548739

	Highly tensile-strained Ge quantum dots on GaSb by MBE for light sources on Si
	Zhang, Zhenpu1,2 ; Song, Yuxin 2; Chen, Qimiao 2; Gong, Qian 2; Wang, Shumin1,2,3
	2016
会议录名称	2016 IEEE PHOTONICS SOCIETY SUMMER TOPICAL MEETING SERIES (SUM)
页码	82-83
发表状态	已发表
DOI	10.1109/PHOSST.2016.7548739
摘要	It is theoretically predicted that biaxial tensile strain as much as 1.4% can make up the 136 meV gap between the Γ and L valley in Ge [1], thereby converting Ge from an indirect-bandgap semiconductor into a direct-bandgap one that can emit light efficiently covering the telecom band. The mobility of both carriers is dramatically increased simultaneously. Therefore, tensile-strained Ge has drawn large interest in the potential for high speed transistors and light sources for Si photonics. We have proposed and demonstrated that tensile-strained Ge quantum dot (QD) on InP is a better solution for the realization of light sources on Si than thin films since it can hold large strain to convert the bandgap and insensitive to structural defects at the same time [2]. In this work, the molecular beam epitaxy (MBE) of tensile-strained Ge QDs on GaSb(001) with thickness ranging from sub-monolayer (ML) to a few MLs is studied. The formation and evolution of the deposited Ge QDs are investigated by the reflection high-energy electron diffraction (RHEED), and the surface morphology is measured by atomic force microscopy (AFM). In FIG. 1, it is shown that the RHEED pattern changed to a dotty one after 1.7 ML of the Ge deposition indicating a Stranski-Krastanov (SK) growth mode with the existence of a wetting layer. FIG. 2 are AFM images of the samples with different Ge thickness. It can be found that when the thickness is below one ML, the Ge atoms nucleate randomly on the GaSb atomic steps, forming sub-ML islands. The two dimensional growth continues to a full coverage of the GaSb surface and up to 1.7 ML. A few QDs can be found before 1 ML, probably due to surface defects. These sub-ML islands and the one ML thick Ge films are fully strained (7.2% tensile strain). When the thickness is larger than 1.7 ML, clear formation of QDs is observed. The QDs are mostly rectangular shape with the edges along the (110) directions. The evolution observed from RHEED and AFM is consistent. Later, samples of the Ge with different thicknesses capped by GaSb were also grown. Further analysis including optical properties are under implement.
关键词	Germanium Tensile strain Stranski-Krastanov growth quantum dots
出版地	345 E 47TH ST, NEW YORK, NY 10017 USA
会议地点	Newport Beach, CA
会议日期	11-13 July 2016
URL	查看原文
收录类别	CPCI
语种	英语
WOS研究方向	Engineering
WOS类目	Engineering, Electrical & Electronic
WOS记录号	WOS:000386968000042
出版者	IEEE
原始文献类型	Proceedings Paper
来源库	IEEE
引用统计	正在获取...
文献类型	会议论文
条目标识符	https://kms.shanghaitech.edu.cn/handle/2MSLDSTB/2009
专题	物质科学与技术学院信息科学与技术学院_特聘教授组_王庶民组物质科学与技术学院_博士生
通讯作者	Song, Yuxin
作者单位	1.Shanghaitech Univ, Sch Phys Sci & Technol, Shanghai 200050, Peoples R China 2.Chinese Acad Sci, Shanghai Inst Microsyst & Informat Technol, State Key Lab Funct Mat Informat, Shanghai 200050, Peoples R China 3.Chalmers, Dept Microtechnol & Nanosci, S-41296 Gothenburg, Sweden
第一作者单位	物质科学与技术学院
第一作者的第一单位	物质科学与技术学院
推荐引用方式 GB/T 7714	Zhang, Zhenpu,Song, Yuxin,Chen, Qimiao,et al. Highly tensile-strained Ge quantum dots on GaSb by MBE for light sources on Si[C]. 345 E 47TH ST, NEW YORK, NY 10017 USA:IEEE,2016:82-83.