Suppressing photoexcited electron-hole recombination in MoSe2/WSe2lateral heterostructuresviainterface-coupled state engineering: a time-domainab initiostudy

Photoexcited carrier dynamics at the interface play a vital role in two-dimensional heterostructure-based photovoltaic and photoelectric devices. This study systematically investigates how the interface morphologies (i.e., alloy and sharp interfaces) control the photogenerated carrier transfer and electron-hole recombination processes in MoSe2/WSe(2)lateral heterostructures. It is revealed that both interfaces exhibit a remarkable photogenerated carrier separation rate within a few picoseconds. More surprisingly, the sharp interface exhibits an exceptional long carrier lifetime up to 1 nanosecond, which is longer than that of the alloy interface by a factor of 1.5. This is ultimately attributed to the vanishing interface-coupled states that effectively limit the transition channel and suppress the electron-hole recombination. This study provides insights into the photogenerated carrier dynamics in heterostructure interfaces and sheds light on the rational design of high-performance transition metal dichalcogenide heterostructure-based photovoltaic and photoelectric devices.