Chestnut Hill, Mass (8/5/2026) – Researchers created an electrically tunable quantum nano-scale corral that traps charged excitons and enables precise electrical control of tiny light sources, including their brightness, color, and quantum states, the team led by Boston College physicists reports today in Nature Nanotechnology.
The findings open up new ways to control hybrid charge, photon, and spin quantum states.
The researchers created a tiny, electrically controlled “trap” that can hold special light-emitting particles in an ultra-thin material called tungsten diselenide (WSe₂), according to Boston College Associate Professor of Physics Qiong Ma, a lead author of the report with Boston College Professor of Physics Kenneth Burch.
The trap is formed by an extremely thin, porous metal layer that produces very small, focused electric fields. The fields allow certain charged particles to be held in place by surrounding neutral ones.
“The trapping is strong enough that we can clearly see distinct energy levels when we measure the light they emit,” said Ma. “We also showed that we can turn this trapping effect on and off using electricity, switching between tightly confined particles and ones that move more freely.”
Ma said the findings were unexpected, as the project was set up to study a different effect. But while examining the device structure for other purposes, the team noted an anomalous signal.
“We noticed unusually strong and discrete light emission from a very small region, which prompted us to investigate its origin,” said Ma, joined on the project by postdoctoral researcher Zumeng Huang, former postdoctoral scholars Zhe Sun and Jian Tang, as well as six graduate students.
After considering several possible explanations, Ma and her colleagues determined the behavior arises from a quantum confinement effect of hybrid charge–photon states.
“Realizing this was both new and intriguing, we became quite excited about its implications,” said Ma, whose research has been funded by the National Science Foundation, CIFAR, and the Alfred P. Sloane Foundation. “Guided by this insight, we then designed additional experiments to rigorously demonstrate and confirm the phenomenon.”
The work is driven by the requirements of future quantum technologies for efficient ways to connect matter-based quantum states with light, Ma said. One promising approach uses excitons—quasiparticles formed when light creates bound electron-hole pairs inside a semiconductor. Excitons interact strongly with light, making them attractive for quantum communication and photonic technologies.
But confining and controlling charged excitons at nanometer length scales has remained difficult because they are composite objects containing multiple interacting particles, Ma said. Developing reliable methods to trap and manipulate them is an important step toward tunable quantum light sources and quantum information devices.
We studied composite charged excitons in monolayer tungsten diselenide (WSe₂), a two-dimensional semiconductor. To confine these excitons, Ma and her colleagues developed an electrostatic “nanocorral” using a nanoporous metallic monolayer of tantalum iridium telluride (TaIrTe)₄ that acts as an electric-field mask.
The compound is a layered material that can be peeled down to atomically thin sheets, similar to graphene, and it conducts electricity while remaining flexible at the nanoscale, said Ma. The nanopore in tantalum iridium telluride is created mechanically through exfoliation—a common method for producing ultrathin layers—where, under carefully controlled conditions and due to the material’s unique mechanical properties, nanoscale holes can form.
The holes serve as precise masks that shape the local electric field at extremely small scales, the team reported. By applying gate voltages and performing low-temperature optical spectroscopy, including photoluminescence and reflectance measurements, the team directly observed discrete quantum-confined excitonic states and tracked their evolution under electrical control.
The discovery surprised Ma and her team.
“Once we identified that the anomalous signal indicated the quantum confinement of a charged exciton, we were surprised to find that charged excitons could be confined in such a robust, electrically tunable, and spectroscopically resolvable manner,” she said. “Previous approaches typically confined only part of the exciton or lacked the nanoscale precision needed to reveal clear quantum signatures.”
Ma said the next challenge is to achieve deterministic control of the nanocorral geometry and ultimately reach a two-level quantum regime. That could enable single-photon sources, photon-correlation measurements, and scalable architectures for quantum networking, quantum communication, and quantum photonic technologies.
Nature Nanotechnology
Experimental study
Not applicable
Electrostatic quantum nanocorral for composite charged excitons
5-Aug-2026