Localized surface plasmon (LSP) effects due to Ag and Ag/SiO2 nanoparticles (NPs) deposited on GaN/InGaN multiquantum well (MQW) light‐emitting diode (LED) structures are studied. The colloidal NPs are synthesized by a sol‐gel method and drop‐cased on the LED structures. The surface density of NPs its controlled by the concentration of the NP solution. Theoretical modeling is performed for the emission spectrum and the electric field distribution of LSP resonance for Ag/SiO2 NPs. Enhanced photoluminescence (PL) efficiency is observed in the LED structures and the amount of PL enhancement increases with increasing the surface density of Ag and Ag/SiO2 NPs. These effects are attributed to resonance coupling between the MQW and LSP in the NPs. It is also shown that the PL enhancement attainable with Ag NPs and Ag/SiO2 NPs is comparable, but the latter displays a much higher stability with respect to long‐term storage and annealing due to a barrier for NP agglomeration, Ag oxidation, and impurity diffusion provided by the SiO2 shell.

Undoped epitaxial films of α-Ga2O3 were grown on basal plane sapphire substrates by halide vapor phase epitaxy (HVPE) in three different modes: standard HVPE, HVPE with constant flow of Ga and pulsed supply of O2 (O2-control growth regime), and with constant flow of O2 and pulsed delivery of Ga (Ga-control growth fashion). The best crystalline quality as judged by x-ray symmetric and asymmetric reflection half-widths and by atomic force microscopy morphology profiling was obtained with the O2-control deposition, and these results appear to be the best so far reported for α-Ga2O3 films. All grown α-Ga2O3 epilayers were high-resistivity n-type, with the Fermi level pinned near Ec − 1 eV deep traps. Photoinduced current transient spectra also showed the existence in standard HVPE samples and samples grown under the O2-control pulsed growth conditions of deep hole traps with levels near Ev + 1.4 eV whose density was suppressed in the Ga-control pulsed HVPE samples. The levels of the dominant deep traps in these α-Ga2O3 samples are close to the position of dominant electron and hole traps in well documented β-Ga2O3 crystals and films.

In this study, we propose and demonstrate efficient electron-hole pair injection from InGaN/GaN multiple quantum well nanopillars (MQW-NPs) to CdSe/ZnS core/shell nanocrystal quantum dots (NQDs) via Förster-type nonradiative energy transfer. For that we hybridize blue-emitting MQW-NPs with red-emitting NQDs and the resultant exciton transfer reaches a maximum rate of (0.192 ns)−1 and a maximum efficiency of 83.0%. By varying the effective bandgap of core/shell NQDs, we conveniently control and tune the excitonic energy transfer rate for these NQD integrated hybrids, and our measured and computed exciton transfer rates are found to be in good agreement for all hybrid cases.

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A free-standing GaN layer was produced by combining electrochemical (EC) etching from the front surface, photo-electrochemical (PEC) etching from the back surface, and subsequent regrowth of GaN on the porous template thus produced. The EC etching resulted in the formation of etch channels on the surface portion of the starting film, whereas the back-side PEC etching gave rise to a columnar structure supporting the entire film. When the n-GaN layer was regrown on such template, the underlying columnar structure provided weak places for easy separation and transfer of the film by mechanical bonding.