Symmetry regimes for circular photocurrents in monolayer MoSe2

Understand

In monolayer transition metal dichalcogenides helicity-dependent charge and spin photocurrents can emerge, even without applying any electrical bias, due to circular photogalvanic and photon drag effects.

• Exploiting such circular photocurrents (CPC) in devices, however, requires better understanding of their behavior and physical origin.
• Here, we present symmetry, spectral, and electrical characteristics of CPC from excitonic interband transitions in a MoSe2 monolayer.
• The dependence on bias and gate voltages reveals two different CPC contributions, dominant at different voltages and with different dependence on illumination wavelength and incidence angles.