Nanoscale Electrical Tuning of Charged Excitons in Two-Dimensional Materials with 1-nm Gate

Tunable localization of charge carriers becomes a critical tool in creating and confining quantum dots within the complex landscape of low-dimensional materials. However, current methods for electrical tunability fall short in scalability and density, posing challenges for high-precision, solid-state semiconducting quantum platforms. Here, we engineer an architecture that achieves electrical tuning in monolayers of transition metal dichalcogenides (TMDCs) at the nanoscale. This platform requires minimal lithography and was made possible by the progress in the synthesis, transfer, and alignment of carbon nanotubes (CNTs) which enabled advanced electronics including 1-nm gates and high-density molybdenum disulfide (MoS₂) transistors. Our measurements confirmed the electrostatic doping effect, leading to exciton-trion conversion processes at 4k. We observed the photoluminescence (PL) spectral behavior of neutral excitons (X^o), charged trions (X^-), and charged biexcitons (XX^-) under various applied biases. Multiphysics simulations showed a doping radius around 15 nm with a pathway to reduce the size down to the Bohr radius limit. This trion state serves as a crucial interface between spin and photons, paving the way for quantum networks and long-range quantum communication. Realizing scalable arrays of indistinguishable and electrically tunable quantum emitters will open doors to diverse quantum photonic technologies, from quantum networks to sensing and simulation.