Dramatically Prolonged Photoexcited Carrier Lifetimes in Group-III Monochalcogenide Heterostructures through Stacking Modulation

Abstract

Modulating the carrier dynamics to achieve the effective separation of photoexcited carriers is crucial for enhancing photoelectric conversion efficiency and advancing high-performance optoelectronic devices. A prototype group-III monochalcogenide heterostructure, GaSe/GaTe, has been proposed to exhibit a superior light-harvesting capability and highly tunable charge separation characteristics via nonadiabatic molecular dynamics (NAMD) simulations. The significant influence of stacking patterns on carrier dynamics is revealed, with electron (hole) transfer occurring within 97 (40) to 390 (126) fs, while the carrier lifetime is dramatically prolonged from 12 to 213 ns, facilitating effective electron–hole (e-h) pair separation. Notably, the AA′ and A′A stacking configurations demonstrate remarkably extended carrier lifetimes of 213 and 161 ns, respectively, exceeding those observed in other 2D heterostructures. The weak nonadiabatic coupling and low-frequency phonon vibrational modes suppress e-h recombination, leading to a prolonged carrier lifetime. These findings offer atomic insights into stacking-dependent carrier dynamics, advancing 2D optoelectronic device design.