We demonstrate room-temperature electroluminescence (EL) from light-emitting diodes (LED) on highly strained germanium (Ge) membranes. An external stressor technique was employed to introduce a 0.76% bi-axial tensile strain in the active region of a vertical PN junction. Electrical measurements show an on-off ratio increase of one order of magnitude in membrane LEDs compared to bulk. The EL spectrum from the 0.76% strained Ge LED shows a 100nm redshift of the center wavelength because of the strain-induced direct band gap reduction. Finally, using tight-binding and FDTD simulations, we discuss the implications for highly efficient Ge lasers.
@article{arxiv.1202.3530,
title = {Electroluminescence from Strained Ge membranes and Implications for an Efficient Si-Compatible Laser},
author = {Donguk Nam and David Sukhdeo and Szu-Lin Cheng and Arunanshu Roy and Kevin Chih-Yao Huang and Mark Brongersma and Yoshio Nishi and Krishna Saraswat},
journal= {arXiv preprint arXiv:1202.3530},
year = {2015}
}