Abstract
Graphene quantum dots (GQDs) can be highly beneficial in various fields due to their unique properties, such as having an effective charge transfer and quantum confinement. However, defects on GQDs hinder these properties, and only a few studies have reported fabricating high-quality GQDs with high crystallinity and few impurities. In this study, we present a novel yet simple approach to synthesizing high-quality GQDs that involves annealing silicon carbide (SiC) under low vacuum while introducing hydrogen (H) etching gas; no harmful chemicals are required in the process. The fabricated GQDs are composed of a few graphene layers and possess high crystallinity, few defects and high purity, while being free from oxygen functional groups. The edges of the GQDs are hydrogen-terminated. High-quality GQDs form on the etched SiC when the etching rates of Si and C atoms are monitored. The size of the fabricated GQDs and the surface morphology of SiC can be altered by changing the operating conditions. Collectively, a novel route to high-quality GQDs will be highly applicable in fields involving sensors and detectors.
Highlights
Graphene quantum dots (GQDs), composed of few graphene layers with a size less than 30 nm, have attracted research interest due to their unique properties, such as possessing a large surface area, low toxicity and strong and tunable photoluminescence [1,2,3,4]
The solutions of the GQDs were centrifuged at 8000 rpm with 10,000 molecular weight cut-off (MWCO) microfilters to eliminate any large particles that were detached from the substrates
The highly prevalent 2D band, the clear lattice spacing and the lack of impurities indicate that the synthesized GQDs are of high quality, with only a few defects on the basal plane
Summary
Graphene quantum dots (GQDs), composed of few graphene layers with a size less than 30 nm, have attracted research interest due to their unique properties, such as possessing a large surface area, low toxicity and strong and tunable photoluminescence [1,2,3,4]. With these advantageous characteristics, GQDs can be used for bioimaging [5,6], biosensing [7], photovoltaics [8,9], drug delivery [10,11] and optoelectronic devices [12,13]. Only a few studies have reported fabricating high-quality GQDs; producing GQDs that have high crystallinity, few defects and high purity is of great importance as GQDs have many promising applications in fields involving sensors and detectors [4,28]
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