Bulk photovoltaic effect in partial overlap MoSe2-WSe2 van der Waals heterostructures: An ab initio quantum transport study. (November 2022) - Cao, Jiang
Abstract: Two-dimensional (2-D) materials, especially transition metal dichalcogenides (TMDCs), have attracted great attention due to their unique properties and the vast possibility they offer when combined into van der Waals heterostructures (vdWHs), for example in optoelectronic applications. Although various photodetectors based on TMDC vdWHs have been successfully synthesized, an ab initio simulation framework dedicated to such devices is still missing. In this work, we investigate two photodetector designs based on MoSe2 -WSe2 vdWHs through a recently developed approach combining density functional theory and quantum transport calculations. Geometries with a partial and total TMDC overlap are considered, with a p-doped (n-doped) left (right) extension and an intrinsic region in the middle. We show that the partial overlap structure supports a non-zero photo-current, even without a p–n junction, and gives rise to the bulk photovoltaic effect (BPVE). The present results provide an easy-to-fabricate guideline for engineering the BPVE in the TMDC vdWHs. Highlights: We investigate two photodetector designs based on MoSe2 -WSe2 heterostructures through DFT + NEGF. We demonstrate non-zero photocurrent without built-in potential with partial overlap. The interlayer absorption and asymmetrical structure result in the unusual BPVE.