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A highly efficient solution-processible charge trapping medium is a prerequisite to developing high-performance organic nano-floating gate memory (NFGM) devices. Although several candidates for the charge trapping layer have been proposed for organic memory, a method for significantly increasing the density of stored charges in nanoscale layers remains a considerable challenge. Here, solution-processible graphene quantum dots (GQDs) were prepared by a modified thermal plasma jet method; the GQDs were mostly composed of carbon without any serious oxidation, which was confirmed by x-ray photoelectron spectroscopy. These GQDs have multiple energy levels because of their size distribution, and they can be effectively utilized as charge trapping media for organic NFGM applications. The NFGM device exhibited excellent reversible switching characteristics, with an on/off current ratio greater than 10(6), a stable retention time of 10(4) s and reliable cycling endurance over 100 cycles. In particular, we estimated that the GQDs layer trapped ∼7.2 × 10(12) cm(-2) charges per unit area, which is a much higher density than those of other solution-processible nanomaterials, suggesting that the GQDs layer holds promise as a highly efficient nanoscale charge trapping material.

We demonstrate that Pd nanoparticle/single-walled carbon nanotubes (Pd-SWCNTs) can be used to improve the quality of α-Ga2O3 crystals using halide vapor phase epitaxy (HVPE) methods. We employed Pd-SWCNTs as the nanoepitaxial lateral overgrowth (ELOG) mask instead of typical dielectric microsize materials, such as SiNx or SiO2. Nano-ELOG Pd-SWCNTs were deposited on a (0001) buffer layer using nanospray coating. Cs-corrected TEM (transmission electron microscopy) analysis revealed that the crystal quality of regrown α-Ga2O3 improved owing to both the blocking of dislocations by the nano-ELOG in the Pd NPs and the dislocation bending by the inclined facets. This simple yet effective technique is believed to be applicable to various growth systems and will find diverse applications in other crystal growth processes.