Surface modification on InAs wetting layer by in-situ pulsed laser and the effets on quantum dot growth

In this work, surface modification of InAs wetting layer was carried out during InAs/GaAs (001) quantum dot molecular beam epitaxy growth by in-situ pulsed laser (355 nm/ 10 ns). We investigated the morphology transformation of wetting layer by atomic force microscope. Atomic layer removal and formation of nano holes were observed on the sample surface. It is proposed that the material removal of wetting layer induced by electronic excitation is triggered by In atom vacancies due to the desorption at substrate temperature of 480°C. The effects of surface modification on QD growth were studied by subsequent InAs deposition after laser irradiation. Preferential nucleation in nano holes were found in the experiments. This study provides a novel technique leading to site-controlled to InAs/GaAs (001) QDs fabrication.