Improvement of GaAs Epitaxial Layers by Indium Incorporation

The influence of indium incorporation (0 - 6.5×10¹⁹cm^-) in GaAs OMVPE layers, on near-band-edge optical properties and deep trap content has been investigated. The bound exciton and donor-acceptor recombination lines in photoluminescence (PL) spectra shift toward lower energies versus indium content. This indicates the formation of a very dilute GaInAs ternary compound. The corresponding PL intensities increase by a factor of 10. This improvement in the optical quality of the layers correlates with a decrease in a ratio 10 for chromium-related PL intensities. On the opposite, the EL2 concentration and depth profile determined by DLTS are not affected. We suggest that indium relaxes lattice distorsions arround residual detects and limits the formation of dislocations.