Department of Electrical Engineering, Stanford University , Stanford, California 94305, United States.
Department of Electronic Engineering, Inha University , Incheon 402-751, South Korea.
Nano Lett. 2016 Apr 13;16(4):2168-73. doi: 10.1021/acs.nanolett.5b03976. Epub 2016 Mar 2.
A silicon-compatible light source is the final missing piece for completing high-speed, low-power on-chip optical interconnects. In this paper, we present a germanium nanowire light emitter that encompasses all the aspects of potential low-threshold lasers: highly strained germanium gain medium, strain-induced pseudoheterostructure, and high-Q nanophotonic cavity. Our nanowire structure presents greatly enhanced photoluminescence into cavity modes with measured quality factors of up to 2000. By varying the dimensions of the germanium nanowire, we tune the emission wavelength over more than 400 nm with a single lithography step. We find reduced optical loss in optical cavities formed with germanium under high (>2.3%) tensile strain. Our compact, high-strain cavities open up new possibilities for low-threshold germanium-based lasers for on-chip optical interconnects.
对于构建高速、低功耗的片上光互连来说，一种硅兼容光源是最后缺失的部分。在本文中，我们提出了一种硅基锗纳米线发光体，它包含了低阈值激光器的所有潜在方面：高应变锗增益介质、应变诱导赝同质结构和高 Q 值纳米光子腔。我们的纳米线结构具有很大的增强光致发光能力，可以将腔模式的品质因数提高到 2000 以上。通过改变锗纳米线的尺寸，我们可以在单次光刻步骤中调谐超过 400nm 的发射波长。我们发现，在高（>2.3%）拉伸应变下形成的光学腔中，光损耗减小。我们的紧凑型高应变腔为基于锗的低阈值激光器在片上光互连中开辟了新的可能性。
