Abnormal strain in suspended GeSn microstructures
Journal article, 2018
A suspended GeSn microstructure is realized by a two-step selective wet etching technique with the aim of fully relaxing the compressive strain, promoting the indirect to direct bandgap transition and improving the optical property of GeSn thin films grown on Ge. The compressive strain was found efficiently relaxed, and even unexpected large tensile strain was displayed on regions of the microstructure by micro-Raman spectroscopy. Residual Ge patches under the suspended GeSn microstructure were found by scanning electron microscopy and proved to be the origin of the tensile strain by finite element method simulations. The tensile strain on the surface is beneficial for direct bandgap conversion and carrier accumulation. Significant enhancement of photoluminescence was obtained in the GeSn microstructures than the original thin film.
mu-Raman
FEM
microstructure
strain engineering
PL
GeSn
silicon photonics
Author
Yi Han
Chinese Academy of Sciences
Yuxin Song
Chinese Academy of Sciences
Xiren Chen
Chinese Academy of Sciences
Zhenpu Zhang
ShanghaiTech University
Chinese Academy of Sciences
Juanjuan Liu
Chinese Academy of Sciences
Yaoyao Li
Chinese Academy of Sciences
Zhongyunshen Zhu
ShanghaiTech University
Chinese Academy of Sciences
Hua Huang
Chinese Academy of Sciences
Jun Shao
Chinese Academy of Sciences
Shu Min Wang
Chalmers, Microtechnology and Nanoscience (MC2), Photonics
Materials Research Express
2053-1591 (eISSN)
Vol. 5 3 035901Subject Categories
Materials Chemistry
Other Materials Engineering
Condensed Matter Physics
DOI
10.1088/2053-1591/aaafec