Photoluminescence Studies of InP/InGaP Quantum Structures Grown by a Migration Enhanced Molecular Beam Epitaxy

InP/InGaP quantum structures (QSs) grown on GaAs substrates by a migration-enhanced molecular beam epitaxy method were studied as a function of growth temperature (T) using photoluminescence (PL) and emission-wavelength-dependent time-resolved PL (TRPL). The growth T were varied from 440 degrees C to 520 degrees C for the formation of InP/InGaP QSs. As growth T increases from 440 degrees C to 520 degrees C, the PL peak position is blue-shifted, the PL intensity increases except for the sample grown at 520 degrees C, and the PL decay becomes fast at 10 K. Emission-wavelength-dependent TRPL results of all QS samples show that the decay times at 10 K are slightly changed, exhibiting the longest time around at the PL peak, while at high T, the decay times increase rapidly with increasing wavelength, indicating carrier relaxation from smaller QSs to larger QSs via wetting layer/barrier. InP/InGaP QS sample grown at 460 degrees C shows the strongest PL intensity at 300 K and the longest decay time at 10 K, signifying the optimum growth T of 460 degrees C.