Analysis of enhanced light emission from highly strained germanium microbridges
Analysis of enhanced light emission from highly strained germanium microbridges
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DOI：
10.1038/nphoton.2013.67
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发表时间：
2013-06-01
期刊：
影响因子：
35
通讯作者：
Sigg, H.
中科院分区：
文献类型：
--
作者：
Sueess, M. J.;Geiger, R.;Sigg, H.
拉伸应变是一种广泛讨论的方法，用于在Ge中引入直接带隙，以实现与Si微电子兼容的半导体激光器。我们提出了一种自上而下的制造方法，用于在悬浮的Ge结构中产生高的单轴拉伸应力，该结构增强了由生长在硅或绝缘体上硅衬底上的Ge层的热失配引起的应变的20倍以上。高达3.1%的应变值测量使用拉曼光谱，在良好的协议与模拟使用双轴热应变为0.15%。正如从高应变值所预期的，观察到相对于体Ge的发射中的210 meV峰值能量偏移和积分光致发光强度的强烈增加（325）。虽然3.1%的单轴应变不会将Ge转变为直接带隙材料，但我们的模型计算预测，在3 x 10（19）cm（-3）的电子空穴注入密度下，1 x 10（19）cm（-3）n掺杂结构的光学增益为460 cm（-1）。
Tensile strain is a widely discussed means for inducing a direct bandgap in Ge for the realization of a semiconductor laser compatible with Si microelectronics. We present a top-down fabrication approach for creating high uniaxial tensile stress in suspended Ge structures, which enhances-by a factor of more than 20-the strain induced by thermal mismatch of Ge layers grown on silicon or silicon-on-insulator substrates. Strain values up to 3.1% are measured using Raman spectroscopy, in excellent agreement with simulations using a biaxial thermal strain of 0.15%. As expected from the high value of strain, a 210 meV peak energy shift in the emission with respect to bulk Ge and a strong increase (325) in the integrated photoluminescence intensity are observed. Although 3.1% uniaxial strain does not transform Ge into a direct-gap material, our model calculation predicts an optical gain of 460 cm(-1) for 1 x 10(19) cm(-3) n-doped structures at an electron-hole injection density of 3 x 10(19) cm(-3).