Terahertz Surface Emission from Layered MoS2 Crystal: Competition between Surface Optical Rectification and Surface Photocurrent Surge

• DOI: 10.1021/acs.jpcc.7b09723
• Publication Date: 2017-12-11T17:19:13Z
• Authors: Yuanyuan Huang; Lipeng Zhu; Zehan Yao; Longhui Zhang; Chuan He; Qiyi Zhao; Jintao Bai; Xinlong Xu
• Keywords: Optical rectification

Terahertz (THz) radiation of layered molybdenum disulfide (MoS2) crystal under femtosecond laser irradiation was observed using THz surface emission spectroscopy variable-angle transmission configuration. Although MoS2 demonstrates inversion symmetry, surface-symmetry breaking will introduce the resonant optical rectification, which is consistent with incident polarization and azimuthal angle dependences from MoS2. However, depletion field induced make an important contribution oblique incidence, saturation due to electrostatic screening effect by photoexcited carriers. This pump-dependent saturable can be fitted well calculation Maxwell equations electromagnetic boundary conditions. The maximum estimated 1.45 × 104 V/cm 130 nm in depth −40° incidence. Interestingly, when tuned 0°, rectification varies 40% 90%. In addition, diagnosed p-type waveforms comparison GaAs(100). results not only afford a comprehensive understanding materials like but also put forward for characterizing interface properties two-dimensional materials.