Hexagonal boron nitride (hBN) has emerged as a promising two-dimensional (2D) material for photonics device due to its large bandgap and flexibility in nanophotonic circuits. Here, we report bright and localized luminescent centres can be engineered in hBN monolayers and flakes using laser irradiation. The transition from hBN to cBN emerges in laser irradiated hBN large monolayers while is absent in processed hBN flakes. Remarkably, the colour centres in hBN flakes exhibit room temperature cleaner single photon emissions with g2(0) ranging from 0.20 to 0.42, a narrower line width of 1.4 nm and higher brightness compared with monolayers. Our results pave the way to engineering deterministic defects in hBN induced by laser pulse and show great prospect for application of defects in hBN used as nano-size light source in photonics.

The light–matter interaction between nitrogen‐doped graphene quantum dots (N‐GQDs) and bismuth telluride (Bi2Te3) nanoplates is investigated. A maximum of (2.9 ± 0.3)‐fold emission rate enhancement is observed at room temperature due to the coupling of N‐GQD emission with the breathing mode of surface plasmon of single Bi2Te3 nanoplates. The enhancement varies with different emission wavelengths and nanoplate diameters in accordance with results obtained through the dipole radiation power in the electromagnetic simulations. From experiment, the quantum yield of N‐GQDs is obtained to be almost unity, while Bi2Te3 nanoplates may replace the conventional antenna. Such combination of novel active and plasmonic materials is promising for efficient lighting applications with multiple functionalities, especially tunable plasmonic metamaterial based on topological insulators.

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We present the synthesis and characterization of gallium nitride (GaN) pine tree-like nanostructures (PTLNs) grown by low-pressure chemical vapor deposition. A high yield of PTLNs is densely arranged with each PTLN having a typical length of 15.46 ± 3.38 μm. From Raman spectroscopy, we observe an E 2 H peak at 570 ± 6 cm–1 which is the primary characteristic of wurtzite. X-ray and ultraviolet photoemission spectroscopy reveal that the electronic structures of GaN PTLNs indicate an n-type character, while the work function and valence band maximum are determined to be 3.30 ± 0.05 and 3.85 ± 0.08 eV, respectively. We confirm the electronic nature of our structure from the current–voltage characteristics exhibiting rectifying behavior. Density functional theory calculations of GaN PTLNs modeled by germanium-doped GaN nanowires are consistent with our experimental findings. To summarize, the energy-band diagram is presented for the future of GaN PTLNs in the optoelectronic and sensing applications.

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The knowledge of anything, since all things have causes, is not acquired or complete unless it is known by its causes. Ibn Sīnā Acknowledgement S tarted four years ago, this manuscript marks then end of a long journey. My first thanks go to Professor Wang Hong for his continuous support and trust during this period. I am grateful to Doctor Muhammad Danang Birowosuto for his help and experience that allowed us to work efficiently these last years. Thanks also to Professor Philippe Coquet, director of CINTRA lab. Many thanks to Songyan Hou and Aurélien Olivier for all the insightful discussions and experiments we shared. I am thankful to all the staff in NTU for their help maintaining and fixing the equipments so I can work efficiently. A great thank to the Nano-fabrication fabrication center team