Irradiation of quantum semiconductor microstructures with ultraviolet pulsed lasers could induce surface defects and modify chemical composition of the microstructure capping material that during high-temperature annealing leads to selected area bandgap engineering through the process known as quantum well intermixing (QWI). In this work, we investigate the role of both ArF and KrF excimer lasers in the QWI process of InP/InGaAs/InGaAsP microstructures irradiated in air and deionized (DI) water. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy analysis was employed to study the chemical composition of the irradiated surface and investigate the chemical evolution of ArF and KrF laser irradiated microstructures. The results indicate that InPxOy oxides are the dominating surface products of the ArF and KrF lasers interaction with InP. Consistent with this observation is a relatively greater bandgap blue shift of similar to 130 nm found in the microstructures irradiated in air, in comparison to a maximum of 60 nm blue shift observed in the microstructures irradiated in a DI water environment. (c) 2012 Elsevier B.V. All rights reserved.