Photoluminescence in GaAs and In0.7Ga0.3P single layers on InP

Single strained layers of GaAs (25 إ) and In0.7Ga0.3P (100 إ) grown by gas source molecular beam epitaxy between InP barriers have been investigated by low temperature photoluminescence measurements at 2 K. Intense luminescence emission was observed at 1.063 eV from the strained GaAs single quantum well in between InP barriers. The emission is attributable to recombination between the holes confined in the GaAs layer and impurities in the InP barrier in a type-II band gap alignment configuration. However, the structure is believed to be weakly type-II due to the possibility of recombination at deep levels in InP. For the In0.7Ga0.3P/InP structure, there is a broad emission at around 1.08 eV which is associated with deep levels, and InP band edge related peaks at higher energies confirming a band alignment of type-I.