PHOTO-LUMINESCENCE AND LATTICE MISMATCH IN INGAAS/INP

A new photoluminescence (PL) band in LPE InGaAs layers nearly lattice-matched to InP has been observed at 0. 69 ev at 77 K. This PL band has a strong correlation with the degree of the lattice mismatch between InGaAs and InP, and the intensity shows the minimum at the lattice mismatch of minus 0. 08 to about minus 0. 07%. The in-depth profile of the PL intensity has been also measured, the result showing that the intensity slightly increases in the interface regions of InGaAs and InP, though the PL intensity of the InGaAs edge emission is nearly constant in the InGaAs layer. These results are well explained by considering the difference of the lattice parameters of InGaAs and InP at both the LPE growth and room temperature, and might suggest the existence of some defects introduced during the epitaxial growth by the lattice mismatch between InGaAs and InP.