Time resolved photoluminescence of homo- and hetero-epitaxial layers of InP grown on GaAs substrates

InP homoepitaxial layers and heteroepilayers of InP grown on (001) and (111)B surfaces of GaAs substrates by metalorganic chemical vapor deposition, have been investigated using time-resolved photoluminescence spectroscopy. In this study, we have focused on the intrinsic transitions. The measured decay-time for the heteroepitaxial layers of InP exhibited the same temperature dependence as the thermal quenching. The decrease of the decay-time as the temperature increase is attributed to the non-radiative processes, which are thermally activated. It is shown, by comparison with InP homoepitaxial layers, that the PL decay-time for InP on both (111)B and (001) surfaces of GaAs substrates is decreased. The reduction of the measured decay-time is considered to be due to the additional non-radiative processes arising from the threading dislocations. Compared with the InP on GaAs(001), the heteroepilayers on GaAs(111)B substrates exhibited a significant increase in the decay time as a result of the reduction in the threading dislocations density.