Optical properties of lattice-matched GaAsPBi multiple quantum wells grown on GaAs (001)

Quaternary alloy GaAsPBi is a novel III-V compound with attractive optical properties and can in principle be grown lattice-matched to GaAs. However, the practical realization of the alloy by metal-organic vapor phase epitaxy and molecular beam epitaxy (MBE)-the two main growth technologies-is fraught with difficulties. Here, using standard solid-source MBE, GaAsPBi films, and GaAsPBi/GaAs multiple quantum wells (MQW) have been grown lattice-matched to (001) GaAs. The structural integrity of the films/MQW is investigated and confirmed by various in- and ex-situ diffraction and spectroscopic techniques. All GaAsPBi structures-films and MQWs-are luminescent at room temperature. Photoluminescence shows that all the samples exhibit an S-shape temperature dependency, indicating strong localizations. Of most significance to practical applications is the observation that the emission from GaAsPBi MQWs is more efficient than their non-quantum well (QW) counterparts (up to 30x at room temperature). These results confirm the long-known benefits of carrier confinements by QWs, demonstrated here for the first time in the GaAsPBi-based system despite the challenge of the crystal growths.