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 130µ 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 2-layers is predicted at photon energies 7.40 eV and 5.95 eV in the 5-layers of h -BN and β-GeS, respectively.  The two homostructures may thus be promising building blocks for next-generation shift current devices. These findings also suggest layering as a possible convenient approach of enhancing and also tuning the SPC output in thin layered materials.

Keywords: Shift photocurrent, 2D vdW homostructures, h-BN, β-GeS.