Optical Characterization of InAs Quantum Dots Fabricated by Molecular Beam Epitaxy

Optical characterization were performed on patterned InAs dots based on InAs/InAlAs hetero-structure and the self-assembled InAs dots grown on GaAs. Unexpectedly high peak energy shift in photoluminescence (PL) and cathodoluminescence (CL) was observed from InAs dots based on InAs/InAlAs heterostructure. PL results of self assembled InAs dots grown on GaAs also showed unexpectedly high peak energy. CL spectra from each single InAs dot suggested luminescence from highly strained dots contribute to shift the average luminescence peak towards higher energy. The high PL peak energy from the self-assembled InAs dots turned out to be composed of strain-induced band-gap widening (28%), carrier confinement effect (17%) in addition to unstrained band-gap energy (29%). 26% of the total PL peak energy remained unassigned.