Qi Zhipeng, Sun Hao, Luo Manlin, Jung Yongduck, Nam Donguk
School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore.
J Phys Condens Matter. 2018 Aug 22;30(33):334004. doi: 10.1088/1361-648X/aad0c0. Epub 2018 Jul 3.
Strained germanium nanowires have recently become an important material of choice for silicon-compatible optoelectronic devices. While the indirect bandgap nature of germanium had long been problematic both in light absorption and emission, recent successful demonstrations of bandstructure engineering by elastic strain have opened up the possibility of achieving direct bandgap in germanium, paving the way towards the realization of various high-performance optical devices integrated on a silicon platform. In particular, the latest demonstration of a low-threshold optically pumped laser in a highly strained germanium nanowire is expected to vitalize the field of silicon photonics further. Here, we review recent advances and challenges in strained germanium nanowires for optoelectronic applications such as photodetectors and lasers. We firstly introduce the theoretical foundation behind strained germanium nanowire optoelectronics. And several practical approaches that have been proposed to apply tensile strain in germanium nanowires are further discussed. Then we address the latest progress in the developments of strained germanium nanowire optoelectronic devices. Finally, we discuss the implications of these experimental achievements and the future outlook in this promising research field.
应变锗纳米线最近已成为硅兼容光电器件的重要材料选择。虽然锗的间接带隙特性长期以来在光吸收和发射方面都存在问题，但最近通过弹性应变实现能带结构工程的成功示范，为在锗中实现直接带隙开辟了可能性，为实现集成在硅平台上的各种高性能光学器件铺平了道路。特别是，最近在高应变锗纳米线中实现的低阈值光泵浦激光器有望进一步推动硅光子学领域的发展。在此，我们回顾了应变锗纳米线在光探测器和激光器等光电子应用方面的最新进展和挑战。我们首先介绍应变锗纳米线光电子学背后的理论基础。并进一步讨论了已提出的在锗纳米线中施加拉伸应变的几种实际方法。然后我们阐述了应变锗纳米线光电器件开发的最新进展。最后，我们讨论这些实验成果的意义以及这个充满前景的研究领域的未来展望。
