2D Atomic Layer Energy and Hot Carrier Transport

2D atomic-layer materials exhibit unique physical properties, which prompt great opportunity for broad potential applications. The contact condition at the  interface is a main factor in determining the interfacial phonon coupling and energy exchange. The extremely thin thickness of 2D materials makes it very challenging to study the local interface energy coupling and the bonding condition. In our lab, systematic and pioneering studies have been conducted to develop novel Raman techniques, including TD-Raman, FR-Raman, and ET-Raman to study 2D material's own thermal and charge carrier transport, interface energy transport, and electron-hole recombination.

We are the first lab in the world that distinguished the hot carrier-phonon transport in 2D materials, overcame the optical interference and local stress effect in thermophysical properties characterization of 2D materials, distinguished the optical-acoustic phonon temperatures, and determined their energy coupling coefficient.

Representative publications:

1. Jingchao Zhang, Yongchun Wang, Xinwei Wang, 2013, "Rough Contact Not Always Bad for Interfacial Energy Coupling," Nanoscale, 5, 11598.

2. Yanan Yue, Jingchao Zhang, and Xinwei Wang, 2011, "Micro/Nanoscale Spatial Resolution Temperature Probing for Interface Thermal Characterization between Epitaxial Graphene and 4H-SiC," Small, 7, No. 23, 3324–3333.

3. Hamidreza Zobeiri, Nicholas Hunter, Ridong Wang, Tianyu Wang, and Xinwei Wang, 2021, "Direct Characterization of Thermal Non-equilibrium between Optical and Acoustic Phonons in Graphene Paper under Photon Excitation," Advanced Science, 2004712.

4. Ridong Wang, Hamidreza Zobeiri, Yangsu Xie, Xinwei Wang, Xing Zhang, Yanan Yue, 2020, "Distinguish Optical and Acoustic Phonon Temperatures and Their Energy Coupling Factor under Photon Excitation in nm 2D Materials," Advanced Science, 2000097 (Supporting information).

5. Hamidreza Zobeiri, Ridong Wang, Qianying Zhang, Guangjun Zhu, Xinwei Wang, 2019, "Hot Carrier Transfer and Phonon Transport in Suspended nm WS₂ Films," Acta Materialia, Vol. 175, 222-237.

6. Pengyu Yuan, Ridong Wang, Hong Tan, and Xinwei Wang, 2017, "Energy Transport State Resolved Raman for Probing Interface Energy Transport and Hot Carrier Diffusion in Few-Layered MoS₂," ACS Photonics, Vol. 4, pp. 3115-3129 (Supporting Information).

7. Pengyu Yuan, Jing Liu, Ridong Wang, and Xinwei Wang, 2017, "Hot Carrier Diffusion Coefficient of Sub-10 nm Virgin MoS₂: Uncovered by Non-contact Optical Probing," Nanoscale, 9, 6808.

8. Nicholas Hunter, Nurul Azam, Hamidreza Zobeiri, Ridong Wang, Masoud Mahjouri-Samani, and Xinwei Wang, 2020, "Interfacial Thermal Conductance between Monolayer WSe₂ and SiO₂ under Consideration of Radiative Electron-hole Recombination," ACS Applied Materials and Interfaces, Vol. 12, 51069-51081.