Effects of high energy proton implantation on the optical and electrical properties of In(Ga)as/GaAs QD heterostructures with variations in the capping layer

This study reports enhancements in photoluminescence (PL) efficiency resulting from implanting InAs/GaAs quantum dots with high energy protons without any post-annealing treatment and discusses the effects that result from varying the capping layer over dots. The PL efficiency for proton-implanted samples increased when the fluence of the 3 MeV protons improved from 8.0×1011 to 1.0×1013 ions/cm2. Up to a certain point, variations in the proton energy level improved the PL efficiency. The improvements in PL efficiency resulted from annihilation of defects and non-radiative recombination centers from the dots and capping layer. Increments in the thermal activation energy of the implanted samples confirmed the finding. To determine the validity of the improvement on the optical properties of the dots, we implanted an InGaAs/GaAs quantum dot infrared photodetector (QDIP) heterostructure with 3 MeV protons. The implanted QDIP exhibited suppressed dark current density and enhanced peak detectivity by two orders compared to the as-grown devices.