Re. Pritchard et al., COMPOSITION ASSESSMENT BY SPATIALLY-RESOLVED PHOTOLUMINESCENCE OF INGAAS AND INGAASP EPILAYERS GROWN ON RECESSED INP SUBSTRATES, Semiconductor science and technology, 8(6), 1993, pp. 1166-1172
Epitaxial layers of InGaAs and InGaAsP have been grown on InP recessed
substrates by MOVPE. Spatially resolved photoluminescence (PL) at low
temperatures has been used to assess the quality of material grown bo
th in the bottom of the recess and on the sidewalls. PL Signals from t
ernary and quaternary epilayers grown on a 100 mum wide recess both sh
ow significant perturbations (10-20 meV) in PL energy at the sidewalls
compared with the bulk value. In the middle of the InGaAs recess the
lattice-matched PL energy is not re-established, with a blue shift ind
icating Ga-rich material- For the InGaAsP recess a smaller blue shift
in PL energy from the middle of the recess is observed. The effect of
growth parameters (reactor pressure and gas flow rate) and the influen
ce of recess width on the perturbation to the PL energy and quality of
the InGaAs epilayers described above has also been evaluated.