Photoluminescence of InGaP/GaAs (111) LPE Layers with Elastic Strain due to Lattice Mismatch

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Abstract
The influence of the elastic strain due to a lattice mismatch on the photoluminescence spectrum was studied. Energy shifts in the band-to-band emission were measured as a function of the misfit strain for InGaP layers grown on GaAs (111)A and (111)B substrates. The shift in bandgap energy was proportional to the lattice mismatch in the range (Δa/a 0)f\lesssim0.16%. When (Δa/a 0)f>0.16%, the shifts in the bandgap energy were nearly constant. These results show that the misfit strain induced by the lattice mismatch was accommodated elastically for (Δa/a 0)f\lesssim0.16%. For larger values of (Δa/a 0)f, misfit-dislocations were introduced and the grown layers were deformed plastically in part. Sub-band emissions observed below the band-to-band emission became minimal when the epitaxial layer was lattice-matched to a GaAs substrate at the growth temperature.