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Monolayer transition metal dichalcogenides support various types of excitonic complexes due to the strong vertical confinement and reduced dielectric screening¹. Electrostatic gating plays a crucial role to control the excitonic complexes and enables a wide-range of optoelectronic and quantum applications². However, gating in a nanoscale region and its effect on the excitonic complexes remains an open question. Here, we show that a conductive nanoscale tip induces a local emission peak around 1.67 eV, which is clearly distinguished from the surrounding area in a monolayer WSe₂. Electrical and photophysical experiments reveal that the local peak is energy-tunable and different from trionic or biexcitonic emission. Our results open the possibility of confining and controlling excitonic complexes at cryogenic temperature.

1. M. Barbone et al., Nature Communications 9, 3721 (2018)
2. T. Mueller and E. Malic, npj 2D Materials and Applications 2, 29 (2018)