Optical Properties of Closely Coupled Dilute Nitride Mid-Infrared InNSb Quantum Dots

We report the growth and characterization of a new dilute nitride, InNSb quantum dots embedded on both InAs and GaAs substrate. Strain induced, self-assembled quantum dots are grown using solid-source molecular beam epitaxy. For improved growth control, we developed a growth technique similar to atomic layer epitaxial methods. Nitrogen incorporation during formation of quantum dots changes surface energy barrier and causes anisotropic distribution of strain energy, results in formation of closely coupled multiple quantum dots in 110 orientation. We obtained mid infrared luminescence around 3.6 micron from InNSb QDs grown on InAs substrate, where it exhibits relatively low efficiencies of nitrogen incorporation compared to the quantum well structure. The band structure calculation confirms band-anticrossing occurs with localized nitrogen energy band, EN 0.42 eV, and results in energy band gap reduction of 50 meV with adding 1 of nitrogen.