Nikita Chanda

Major: Physics
Mentors: Sean Doan, Professor Galan Moody

Electrically Tunable Defect-Based Quantum Emitters in hBN-Graphene Heterostructures

Reliable and efficient electrical tunability is essential for integrating defect-based quantum emitters into scalable quantum technologies such as photonic quantum computation, communication, and networking. For practical implementation, these sources must maintain stable charge states, demonstrate Stark tuning, and exhibit minimal spectral diffusion under electrical control. We choose defects in van der Waals materials due to their unique advantages such as optimal surface operation and compatibility with heterostructure fabrication for proximity-effect coupling. Here, we investigate how electrostatic gating influences the quantum optical properties of defect-based quantum emitters in hexagonal boron nitride (hBN) when combined with graphene in vdW heterostructures. While quantum emitters in hBN and electrical gating have been independently studied, the impact of gating on their optical stability, emission intensity, charge state, and defect-specific responsiveness remains unclear. To address this, we fabricate hBN-graphene heterostructures via exfoliation, solvent cleaning, and stacking of individual flakes. Defects are introduced through O₂ plasma treatment, and atomic force microscopy is used to identify optimal sample regions. We apply gate voltages and laser excitation to induce and characterize single-photon emission. Our results aim to demonstrate stable, electrically tunable single-photon emission and provide insight into the mechanisms of gating response in 2D defect-based quantum systems. This study addresses key knowledge gaps in gating efficiency and defect response, advancing the development of stable, electrically controllable quantum light sources for integration into quantum photonic systems.