Studies on group III-nitride quantum dots grown on three-dimensional structures

Abstract

Group III-nitride semiconductors have been received much attention for optoelectronic devices. These include manipulation of emission wavelength from ultraviolet (~210 nm) to near infrared (~1.7 μm) via quaternary alloy $Al_xGa_{1-x}In_yN$, p-type doping and large exciton binding energy. In particular, semiconductor quantum dots (QDs) possess a variety of attractive properties for classical and quantum light source. In this dissertation, we proposed the group III-nitride QDs grown on three-dimensional structures for broadband ultraviolet light emitter and single photon emitter, respectively. For the broadband ultraviolet light emitter, we fabricated ensemble GaN QDs grown on hexagonal truncated pyramid structures. Consequently, it ultimately rendered a broadband ultraviolet spectrum range covering from ~400 nm to ~270 nm with high efficiency. For the single photon emitter, we fabricated single InGaN QD grown on nano-pyramid structure. We successfully demonstrated single photon emitter with improved linewidth broadening. We proposed desirable structure design using photoelectrochemical etching method for the improvement of single photon purity even at the elevated temperature. We expect our works can ignite new interests for the community and expand the horizon for QD applications ranged over classical and quantum area.