Limited Mobility in ZnPS₃ Nanosheets under Phonon Scattering and Shockley-Read-Hall Recombination

Unraveling the lattice vibration, carrier dynamics, and their influence on the carrier transport in 2D semiconductors is pivotal for advancing next-generation optoelectronic and optoacoustic devices. Herein, we investigate the spatiotemporal carrier dynamics and transport properties of ZnPS₃ nanosheets using transient absorption microscopy. Our measurements reveal the generation of coherent longitudinal acoustic phonons at 17.58 GHz during early stage dynamics, governed by the deformation potential mechanism. Additionally, we identify a Shockley-Read-Hall process on the nanosecond time scale in ZnPS₃ and demonstrate carrier transport with a limited mobility of 41.5 cm²/(V·s), which is much lower than the theoretical value (226.5 cm²/(V·s)). We attribute the lower mobility to the synergistic effects of strong electron-phonon coupling and defect-mediated scattering in ZnPS₃. This work provides critical insights into the carrier dynamics and transport of ZnPS₃, guiding its optimization for future optoacoustic and optoelectronic device applications.