Optical Voltage Profiling of 2D Semiconductors via Proximal Exciton Sensing
Abstract
High contact resistances in atomically thin semiconductors often mask intrinsic electrical transport properties, particularly at low carrier densities where exotic correlated states emerge. We introduce optical voltage profiling, a noninvasive wide-field technique that replaces local voltage probes with a proximal monolayer MoSe2 exciton sensor. Isolated by thin hexagonal boron nitride, this sensor converts the target's local electrostatic potential into spatially resolved modulations of exciton reflectance. Through pixel-wise in situ calibration, these signals yield quantitative two-dimensional voltage maps of an actively biased semiconductor device. Using this method, we demonstrate the carrier-density-driven metal-insulator transition in bilayer MoSe2 and obtain channel resistances below 1 kΩ despite MΩ-scale two-terminal resistances in the metallic region. The optically derived resistance exhibits a metal-insulator crossover near the resistance quantum h/e2, and the voltage maps and reconstructed local conductivity reveal pronounced spatial heterogeneity in both insulating and metallic regimes. Beyond resolving channel resistance under high contact-resistance conditions, the technique provides spatially resolved access to microscopic transport heterogeneity in functional van der Waals devices.
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BibTeX
@misc{kim2026optical,
title = {{Optical Voltage Profiling of 2D Semiconductors via Proximal Exciton Sensing}},
author = {Ha-Leem Kim and Hyungbin Lim and Yuanyi Yang and Ruishi Qi and Ruichen Xia and Can Uzundal and Takashi Taniguchi and Kenji Watanabe and Feng Wang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.18382},
eprint = {2608.18382},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.18382},
}
RIS
TY - UNPB
TI - Optical Voltage Profiling of 2D Semiconductors via Proximal Exciton Sensing
AU - Ha-Leem Kim
AU - Hyungbin Lim
AU - Yuanyi Yang
AU - Ruishi Qi
AU - Ruichen Xia
AU - Can Uzundal
AU - Takashi Taniguchi
AU - Kenji Watanabe
AU - Feng Wang
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2608.18382
UR - https://arxiv.org/abs/2608.18382
AB - High contact resistances in atomically thin semiconductors often mask intrinsic electrical transport properties, particularly at low carrier densities where exotic correlated states emerge. We introduce optical voltage profiling, a noninvasive wide-field technique that replaces local voltage probes with a proximal monolayer MoSe_2 exciton sensor. Isolated by thin hexagonal boron nitride, this sensor converts the target's local electrostatic potential into spatially resolved modulations of exciton reflectance. Through pixel-wise in situ calibration, these signals yield quantitative two-dimensional voltage maps of an actively biased semiconductor device. Using this method, we demonstrate the carrier-density-driven metal-insulator transition in bilayer MoSe_2 and obtain channel resistances below 1 kΩ despite MΩ-scale two-terminal resistances in the metallic region. The optically derived resistance exhibits a metal-insulator crossover near the resistance quantum h/e^2, and the voltage maps and reconstructed local conductivity reveal pronounced spatial heterogeneity in both insulating and metallic regimes. Beyond resolving channel resistance under high contact-resistance conditions, the technique provides spatially resolved access to microscopic transport heterogeneity in functional van der Waals devices.
ER -