Ultrafast interfacial carrier dynamics and persistent topological surface states of Bi2Se3 in heterojunctions with VSe2

Abstract Vanadium diselenide (VSe 2 ) has recently been highlighted as an efficient 2D electrode owing to its extra-high conductivity, thickness controllability, and van der Waals contact. However, the electrode, applications of VSe various materials are still lacking. Here, by employing ultrafast time-resolved spectroscopy, we study -thickness-dependent interfacial effects in heterostructures with topological insulator Bi Se 3 that is severely affected contact conventional 3D electrodes. Our results show unaltered Dirac surface state against forming junctions , hot electron transfer from across interface, shortened metastable carrier lifetimes due dipole interactions enabling current flow, electronic level shift (~tens meV) bulk states interactions, which ~10 times lower compared electrodes, implying weak Fermi pinning. observations confirm ideal for -based-applications full utilization characteristics.