  Excitons -- quasiparticles formed by the binding of an electron and a hole
through electrostatic attraction -- hold promise in the fields of quantum light
confinement and optoelectronic sensing. Atomically thin transition metal
dichalcogenides (TMDs) provide a versatile platform for hosting and
manipulating excitons, given their robust Coulomb interactions and exceptional
sensitivity to dielectric environments. In this study, we introduce a cryogenic
scanning probe photoelectrical sensing platform, termed exciton-resonant
microwave impedance microscopy (ER-MIM). ER-MIM enables ultra-sensitive probing
of exciton polarons and their Rydberg states at the nanoscale. Utilizing this
technique, we explore the interplay between excitons and material properties,
including carrier density, in-plane electric field, and dielectric screening.
Furthermore, we employ deep learning for automated data analysis and
quantitative extraction of electrical information, unveiling the potential of
exciton-assisted nano-electrometry. Our findings establish an invaluable
sensing platform and readout mechanism, advancing our understanding of exciton
excitations and their applications in the quantum realm.
