A photoluminescence study of hydrogenated GaAs grown on a InP substrate by metalorganic chemical vapor deposition

The effects of hydrogenation on the low-temperature (5 K) photoluminescence properties of GaAs grown on InP substrate by metalorganic chemical vapor deposition are investigated. An emission band at ∼1.4 eV originating from the GaAs/InP interfacial region shows a 30-fold increase in intensity relative to the GaAs band-edge emission after exposure to hydrogen plasma for 30 min at 250 °C. This improvement in intensity is attributed to hydrogen passivation of defects at the heterointerface caused by the large (≊4%) lattice mismatch between GaAs and InP. Annealing the hydrogenated sample at 350 °C nullifies the passivation effect. Further, the 1.4-eV band shifts to higher energy on annealing the sample in the temperature range 150–450 °C with the hydrogenated sample exhibiting a larger shift than the untreated sample. It is suggested that the annealing-induced peak shift arises due to modification of the interface and that it is greater in the hydrogenated sample compared to the untreated sample.