The research team led by Prof. Jin Yong Lee of the Department of Chemistry (co-first author Ph. D. course Hyundong Kim) has defined photocarrier dynamics of MoS2/Au heterostructures varies by their interface patterns through collaborative research with research teams led by Prof. Jihee Kim (Pusan National University). The research was published in Science Advances (IF: 11.7) in January 2025 under the title "Ultrafast Hot Carrier Extraction and Diffusion in MoS2/Au van der Waals Electrode Interface."

The metal electrode is widely used where it requires specific electronic properties, such as light-emitting diodes, photodetectors, and solar cells. One of the useful ways to control the electronic properties is hybridizing with semiconductor materials; however, this can induce midgap state in interface and defect state in semiconductor, so that can reduce lifetime of photocarrier. This study addresses photocarrier dynamics of MoS2/Au heterostructures varies by deposition patterns by studying optoelectronic process including photocarrier’s recombination, transfer and transfer.

In this study, experimental transient pump-probe spectroscopy and simulation have conducted on three different cases: 1. deposited interface, 2. rugged interface, 3. flat interface. According to the kinetics study, the flat interface showed the longest photocarrier lifetime whereas the deposited interface showed the shortest one. Photocarrier dynamics has depicted according to the spectroscopic data. Professor Lee’s team used density functional theory (DFT) calculations to elucidate electronic band structure of each case theoretically. Calculations of transition dipole matrix along band confirmed the difference in photocarrier lifetime. Through this study, it is expected to utilize controlling deposition pattern of semiconductor and metal electrode heterostructures for band gap alignment.

*Title: Ultrafast Hot Carrier Extraction and Diffusion in MoS2/Au van der Waals Electrode Interface