Quantum-Dot Intermixing Enhancement using UV Laser Irradiation

We report the development of an intermixing technique in InGaAs/GaAs quantum-dot (QD) structure using the combination effects of pulsed UV laser irradiation and dielectric induced layer intermixing. Using this method, the quantum-dot intermixing rate is greatly enhanced by group-III vacancies generated by the dielectric cap during annealing. A bandgap shift as large as 180 meV has been measured from a sample exposed to 480 mJ/cm², 150 pulses of 248 nm UV light, and annealed with a 200 nm thick SiO₂ encapsulant layer. Under similar annealing conditions, the non-irradiated SiO₂ and Si _xN_y encapsulated QDs only exhibit bandgap shifts of 18 meV and 91 meV, respectively