The effect of the strain relaxation in InAs/GaAs stacked quantum dots and multiple quantum wells on the Raman spectrum

Olga L. Lazarenkova, Jet Propulsion Laboratory, California Institute of Technology
Paul von Allmen, Jet Propulsion Laboratory, California Institute of Technology
Seungwon Lee, Jet Propulsion Laboratory, California Institute of Technology
Fabiano Oyafuso, Jet Propulsion Laboratory, California Institute of Technology
Gerhard Klimeck, Network for Computational Nanotechnoloy, Electrical Engineering, Purdue University

Abstract

Atomist,ic-level simulations of the Raman shift in InAs/GaAs multiple quantum well (MQW) and stxketl cjuantuni dot (SQD) structures as a function of interlayer separation axe reported. The simulations utilize an aupcmted Krating nxodcl which includes anharmonicity corrections. It is demonstrated that the iiiteract,iori 1,etwet:il ;~iigled ist or led bonds is responsible for the penetration of the strain into the GaAs barrier. This result is in contrast to a complete strain relaxatioll of t,he CaAs barrier which would be predicted by continuurn n~odels. Tension along the growth direction result in the red shift of the GaAs LO Rarnan peak as the bnrrirr thickwss decreases in both, MQW and SQD, structures.