Effect of lattice mismatch and thermal expansion on the strain of CdTe/GaAs heterostructures

Photoluminescence (PL) measurements on CdTe/GaAs heterostructures grown by molecular beam epitaxy (MBE) were carried out to investigate the effect of the lattice mismatch and the thermal expansion on the strain due to the CdT e epitaxial layer thickness in CdTe/GaAs heterostructures. The PL peak of t he acceptor bound exciton shifts toward the higher-energy side with increas ing CdTe film thickness. A new theoretical equation obtained from the strai n on the lattice-mismatched heterostructure is proposed. The values of the strains determined from the PL measurements were in reasonable agreement wi th those determined from the new theoretical calculations taking into accou nt the lattice mismatch together with the thermal expansion difference betw een the CdTe epilayers and the GaAs substrates. These results can help impr ove the understanding of the structural properties of CdTe/GaAs heterostruc tures. (C) 2000 Elsevier Science B.V. All rights reserved.