Abstract
We report electrically tunable spin singlet and triplet exciton emission from atomically aligned transition metal dichalcogenide (TMD) heterostructures. The observation of these states in both 0° and 60° heterostructures provides the stacking orientation degree of freedom for polarization switching in interlayer excitons. We confirm the spin configurations of the light-emitting excitons employing magnetic fields to measure effective exciton factors. The interlayer tunneling current across the TMD heterostructure enables the electrical generation of singlet and triplet exciton emission in this atomically thin p-n junction. We demonstrate tunability between the singlet and triplet exciton photoluminescence via electrostatic gates and excitation power. By tuning the gates and interlayer bias voltage, the electroluminescence of the singlet and triplet can be switched with ratios of 10:1. Atomically thin TMD heterostructure light-emitting diodes thus enable a route for optoelectronic devices that can configure spin and valley quantum states independently.
- Received 13 December 2020
- Revised 7 April 2021
- Accepted 12 April 2021
DOI:https://doi.org/10.1103/PhysRevB.103.L161411
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