Conventional semiconductor heterojunctions and homojunctions are foundational building blocks of optoelectronic devices including solar cells and light-emitting diodes. Non-centrosymmetric two-dimensional (2D) materials enable the engineering of mixed-dimensional heterostructures with complex optoelectronic properties, such as a polarization-dependent photoresponse. A 5-PI collaboration within the Northwestern University MRSEC discovered a strong ‘bulk’ intrinsic photovoltaic effect (BPVE) in 2D SnP2Se6, a van der Waals chiral (R3 space group) semiconductor. The strong BPVE arises from the combination of high carrier mobility and non-centrosymmetric crystal structure, and the response can be tuned by varying the angle between the crystal and the electrodes as well as the angle of the linearly polarized light. The novel symmetry-dependent photoresponse and the high carrier mobility of SnP2Se6 present diverse opportunities for constructing mixed-dimensional heterojunctions with tailorable optoelectronic properties.
Science Advances, 10, eado8272 (2024).
