Electrostatic Nanocorral Traps Charged Excitons for Tunable Quantum Light Sources

Boston College physicists led by Associate Professor Qiong Ma and Professor Kenneth Burch have created the first electrically tunable quantum "nanocorral" that traps charged excitons (trions) inside monolayer tungsten diselenide (WSe₂), enabling direct voltage control over the brightness, color, and quantum states of the emitted light. The work was published August 5, 2026 in Nature Nanotechnology .

How the device works

The trap is formed by placing a nanoporous metallic monolayer of tantalum iridium telluride (TaIrTe₄) on top of the WSe₂ semiconductor. During mechanical exfoliation, nanoscale holes naturally form in the TaIrTe₄ layer. These holes act as precise electric-field masks, concentrating and reshaping the local electrostatic potential at extremely small scales .

Applying gate voltages to the structure alters the potential landscape that charged excitons experience, switching between tightly confined particles (discrete quantum states) and freely moving ones. The trapping is strong enough that distinct energy levels are clearly visible in the emitted light .

Accidental discovery

The project was originally designed to study a different effect. While examining the device structure for other purposes, the team noticed "unusually strong and discrete light emission from a very small region," an anomalous signal that prompted them to investigate its origin .

Evidence confirming genuine quantum confinement