Electroreflectance study of InGaAsP quaternary alloys lattice matched to InP

Characterization of InGaAsP lattice matched to InP has been performed by electroreflectance measurement. For the measurement, In
1-x
Ga
x
As
y
P
1-y
alloys (
0 < y < 1
) were grown on InP substrates using a vertical LPE furnace and Schottky-barrier diodes were fabricated on them. Analysis of the electroreflectance (ER) spectra taken at the low-field condition has enabled us to determine precisely the energies of the fundamental band edge and the corresponding spin-orbit split-off edge of InGaAsP alloys lattice-matched to InP over the whole composition range. The compositional variations of the band edge, its temperature coefficient near room temperature and the spin-orbit splitting of the valence band in the InGaAsP quaternary alloy system are reported.