Linear photogalvanic effects in monolayer WSe2 with defects
Optics Express
|May 9, 2023
Summary
Defects in monolayer tungsten diselenide (WSe2) significantly enhance photoresponse, showing potential for low-power photoelectronic devices. Sulfur substitution yielded the highest photocurrent, while Ga substitution maximized the extinction ratio.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Chemistry
Background:
- Monolayer WSe2 exhibits intrinsic photoresponse without external bias, indicating potential for energy-efficient photoelectronic applications.
- Understanding the impact of defects on photogalvanic effects is crucial for optimizing material performance.
Purpose of the Study:
- To investigate linear photogalvanic effects in defect-engineered monolayer WSe2.
- To explore how various defects influence photocurrent generation and polarization sensitivity.
- To assess the potential of WSe2 for solar cells and polarization detectors.
Main Methods:
- Utilized the non-equilibrium Green's function technique.
- Employed density functional theory calculations.
- Simulated photocurrent response under varying defect types, concentrations, and photon energies.
Main Results:
- Photocurrent exhibits a sinusoidal dependence on polarization angle.
- Monoatomic sulfur substitution dramatically increased photoresponse (28x at 3.1 eV).
- Monoatomic Gallium substitution resulted in the highest extinction ratio (>157x at 2.7 eV).
- Defect concentration impacts photoresponse; Se/W vacancies and S/Te substitutions significantly increase photocurrent, while Ga substitution has minimal effect.
Conclusions:
- Defect engineering in monolayer WSe2 offers a pathway to significantly enhance photogalvanic effects.
- Monolayer WSe2 is a promising material for visible-light solar cells and polarization detectors.
- Specific defects like S substitution and Ga substitution can be tailored for distinct photoelectronic applications.
