Research

Single-Photon Emitters (SPEs), as indicated by their name, emit single photons that could be used as information carriers (or qubits) for quantum information science applications. While SPEs have been discovered in various material platforms, our group works specifically with SPEs in solid-state materials.

In one of my projects, I work with two-dimensional hBN that hosts SPEs at room temperature. By using an atomic force microscope (AFM), I developed a method to deterministically create SPEs in thin hBN flakes that are placed on a chip-compatible silicon substrate. The method has high spatial precision and is contamination-free. Future work will be to deterministically enhance emission from such hBN SPEs with plasmonic/photonic cavities to obtain indistinguishable single photons.

I also work with color centers in diamond including nitrogen-vacancy (NV) centers, silicon-vacancy (SiV) centers and germanium vacancy (GeV) centers. Instead of using bulk diamond crystals, we use nanodiamonds with sizes below 30 nm that could be efficiently coupled with ultrasmall plasmonic cavities to achieve significant brightness enhancement and lifetime shortening. This could potentially enable single-shot spin readout (NV centers) and indistinguishable single photons (SiV centers) at room temperature.

Spin defects in solid-state materials that are optically addressable are suitable for quantum sensing applications. Typically examples include color centers in diamond (e.g., NV centers), silicon carbide and so on. Spin defects in 2D materials are emerging and they offer potentially higher sensitivity as quantum sensors due to their extreme thickness. In this project, I work with boron vacancy (VB-) spin defects that are recenly discovered in hBN and aim to increase their quantum efficiency via plasmonic enhancement.

Hot carriers refer to hot electrons and holes that have energies higher than electrons/holes at thermal equilibrium. In plasmonics, hot carriers could be generated through the non-radiative decay of either surface plasmon polaritons (SPPs) or localized surface plasmons (LSPs). In this project, I investigate the generation of hot electrons from the decay of LSPs in titanium nitride (TiN) nanoparticles. By synthesizing TiN@TiO2 core-shell nanoparticles, we show the transfer of such hot electrons from TiN to TiO2, which demonstrate the potential of TiN for a number of photocatalytic applications.