Self-organized nano-cone arrays in InP/InGaAs/InGaAsP microstructures by irradiation with ArF and KrF excimer lasers

Abstract

We discuss the effect of ArF (λlaser=193 nm) and KrF (λlaser=248 nm) excimer laser irradiation of InP/InGaAs/InGaAsP quantum well (QW) microstructures on surface morphology of the top InP layer. The irradiation was carried out in air with lasers delivering up to 700 pulses of fluence from 82 to 142 mJ/cm2. We observe the formation of nano-cone structures having their period increasing from 450 to 1080 nm for KrF laser, and from 675 to 875 nm for ArF laser, in proportion to the laser fluence and pulse number. The chemical and structural modification of the laser irradiated surface has resulted in the enhancement of the QW photoluminescence emission up to 1.4 times when compared to the non-processed material. Thus, the excimer laser processing of the surface of InP capped InGaAs/InGaAsP QW microstructures using relatively low pulse fluence, has been found attractive for the fabrication of enhanced optical emission semiconductor devices.