Theoretical Investigation of Tensile-Strained GeSn/SiGeSn Multiple Quantum Well Laser Wrapped in Si 3N4 Liner Stressor

A tensile-strained GeSn/SiGeSn multiple quantum well (MQW) laser wrapped in Si
₃
N
₄
liner stressor is designed and characterized theoretically. A biaxial tensile strain is introduced into the GeSn/SiGeSn MQW laser by the Si
₃
N
₄
liner stressor. The boosting effects of tensile strain on the threshold current density Jth and optical gain in GeSn/SiGeSn lasers are attributed to the modulation of energy band structure and carrier distribution in the GeSn wells. Tensile-strained Ge
_0.90
Sn
_0.10
/Si
_0.161
Ge
_0.695
Sn
_0.144
MQW laser wrapped in 500 nm Si
₃
N
₄
liner stressor achieves a Jth reduction from 476 to 168 A/cm
²
and a significant enhancement of optical gain, as compared to the relaxed control device without Si
₃
N
₄
. The design of GeSn/SiGeSn MQW structure wrapped in Si
₃
N
₄
liner stressor provides a practical way to realize high performance GeSn based mid-infrared laser.