First principles calculations of charge shift photocurrent in vdWs slide double layered 2D h-BN and β-GeS homostructures

Abstract

Shift photovoltaic current (SPC) in polar non-centrosymmetric materials has recently emerged as a promising candidate for the next generation photovoltaic devices in which Shockley-Queisser limits are fully overcome. Here, we apply first-principles calculations to predict colossal SPC in the slide bilayers of 2D h-BN and β-GeS vdW homostructures. The large SPC in slide bilayers h-BN and β-GeS reaches 49.3 μAV−2 and 130 μ μAV−2, respectively, in the ultra-violet (UV) region. Increasing the number of layers is further implemented to tune the band structure of the two homostructures. Consequently, giant SPC peaks about 3 times larger than those of the bilayers are predicted at photon energies of 7.40 eV and 5.95 eV in the 5-layers of h-BN and β-GeS, respectively. The two homostructures are thus promising building blocks for next-generation photovoltaic devices. These findings also suggest layering as a possible convenient approach to enhancing and also tuning the SPC output in thin layered materials.