Surface state and optical property of sulfur passivated InP

We report photoluminescence (PL) of indium phosphide (InP) surface passivated by sulfur (S). A three-fold enhancement of band edge emission from the bulk InP was observed after the InP was passivated by ammonium sulfide ((NH4)2S) solution for 10 min. X-ray photoelectron spectroscopy measurements indicate that the oxide at InP surface is removed after being sulfurized in (NH4)2S solution. However, the enhancement significantly decreases for a longer treatment time, which is maybe due to a thick S layer deposited at the InP surface resulting in low light transmission.