Tian Xiangling, Wei Rongfei, Ma Zhijun, Qiu Jianrong
Zhejiang Laboratory, Hangzhou 311100, P.R. China.
Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, P.R. China.
ACS Appl Mater Interfaces. 2022 Feb 16;14(6):8274-8281. doi: 10.1021/acsami.1c23053. Epub 2022 Feb 3.
Optical modulation on ultrashort time scales is both of central importance and an essential operation for applications in photonics and optoelectronics. Here, with a giant bandgap renormalization due to a high density of carrier injected by a femtosecond pulse, we realize an expected broadband saturable absorption in chemical vapor deposition grown monolayer transition-metal dichalcogenide MoSe. Our findings reveal the band edge shift from ∼1.53 to ∼0.52 eV under the pump excitation of 0.80 eV, which is induced by the nonequilibrium occupation of electron-hole states after a Mott transition as well as the increase of carrier temperature.
超短时间尺度上的光调制对于光子学和光电子学应用而言既至关重要又是一项基本操作。在此，由于飞秒脉冲注入的载流子密度高而导致巨大的带隙重整化，我们在化学气相沉积生长的单层过渡金属二卤化物MoSe₂中实现了预期的宽带饱和吸收。我们的研究结果表明，在0.80 eV的泵浦激发下，能带边缘从约1.53 eV 移动到约0.52 eV，这是由莫特转变后电子 - 空穴态的非平衡占据以及载流子温度的升高所引起的。
