Spatiotemporal Mapping of Photocurrent in a Monolayer Semiconductor Using a Diamond Quantum Sensor

Abstract

The detection of photocurrents is central to understanding and harnessing the interaction of light with matter. Although widely used, transport-based detection averages over spatial distributions and can suffer from low photocarrier collection efficiency. Here, we introduce a contact-free method to spatially resolve local photocurrent densities using a proximal quantum magnetometer. We interface monolayer MoS2 with a near-surface ensemble of nitrogen-vacancy centers in diamond and map the generated photothermal current distribution through its magnetic field profile. By synchronizing the photoexcitation with dynamical decoupling of the sensor spin, we extend the sensor's quantum coherence and achieve sensitivities to alternating current densities as small as 20 nA per micron. Our spatiotemporal measurements reveal that the photocurrent circulates as vortices, manifesting the Nernst effect, and rises with a timescale indicative of the system's thermal properties. Our method establishes an unprecedented probe for optoelectronic phenomena, ideally suited to the emerging class of two-dimensional materials, and stimulates applications towards large-area photodetectors and stick-on sources of magnetic fields for quantum control.

arXiv comment19 pages, 4 figures

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• Simultaneous Wide-field Imaging of Phase and Magnitude of AC Magnetic Signal Using Diamond Quantum Magnetometry
• AC susceptometry of 2D van der Waals magnets enabled by the coherent control of quantum sensors
• Imaging current paths in silicon photovoltaic devices with a quantum diamond microscope
• Substrate-controlled dynamics of spin qubits in low dimensional van-der-Waals materials
• Quantum speed limit in quantum sensing
• Suppression of the optical linewidth and spin decoherence of a quantum spin center in a $p$$-$$n$ diode
• Theory of spin center sensing of diffusion
• Interplay between charge and spin noise in the near-surface theory of decoherence and relaxation of $C_{3v}$ symmetry qutrit spin-1 centers
• Enhanced Magnetization by Defect-Assisted Exciton Recombination in Atomically Thin CrCl${}_3$
• Widefield quantum microscopy with nitrogen-vacancy centers in diamond: strengths, limitations, and prospects
• Diamond-on-chip infrared absorption magnetic field camera
• Fast coherent control of nitrogen-14 spins associated with nitrogen-vacancy centers in diamonds using dynamical decoupling
• Quantum simulation of spin-1/2 XYZ model using solid-state spin centers