Photoluminescence emission from as-etched quantum nanodisks fabricated by bio-template and neutral beam etching process
Quantum dot laser diodes are expected to replace conventional semiconductor laser diodes in new high-speed information and communication devices. We successfully fabricated disk-shaped quantum dots using a bio-template and neutral beam etching. Our original top-down process achieved defect-less and a high density of dots from etching process compared with conventional plasma processes. Therefore, we attempted to detect emission from the quantum energy levels in the quantum nanodisks (QNDs) for as-etched sample without post-fabrication process. We prepared 4-stacked GaAs/AlGaAs layer QNDs samples after etching (as-etched) and after regrowth. QNDs samples were investigated by photoluminescence (PL) measurements. Results showed some broad peaks appearing between the bandgaps of GaAs and AlGaAs. We compared our experimental results with energies theoretically estimated energies using a nextnano 3D simulator with QND different diameters. For both type of samples, we found that QND diameters increased from top to bottom. From PL measurement, we observed emission from QNDs for as-etched samples fabricated using our own original top-down process.