Shcherbakov Dmitry, Voigt Greyson, Memaran Shahriar, Liu Gui-Bin, Wang Qiyue, Watanabe Kenji, Taniguchi Takashi, Smirnov Dmitry, Balicas Luis, Zhang Fan, Lau Chun Ning
Department of Physics, The Ohio State University, Columbus, Ohio 43221, United States.
National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States.
Nano Lett. 2024 Apr 3;24(13):3851-3857. doi: 10.1021/acs.nanolett.3c04121. Epub 2024 Mar 19.
A two-dimensional (2D) quantum electron system is characterized by quantized energy levels, or subbands, in the out-of-plane direction. Populating higher subbands and controlling the intersubband transitions have wide technological applications such as optical modulators and quantum cascade lasers. In conventional materials, however, the tunability of intersubband spacing is limited. Here we demonstrate electrostatic population and characterization of the second subband in few-layer InSe quantum wells, with giant tunability of its energy, population, and spin-orbit coupling strength, via the control of not only layer thickness but also the out-of-plane displacement field. A modulation of as much as 350% or over 250 meV is achievable, underscoring the promise of InSe for tunable infrared and THz sources, detectors, and modulators.
二维（2D）量子电子系统的特征在于面外方向上的量子化能级或子带。填充更高的子带并控制子带间跃迁具有广泛的技术应用，如光调制器和量子级联激光器。然而，在传统材料中，子带间距的可调性是有限的。在这里，我们展示了通过控制层厚度和面外位移场，在少层InSe量子阱中实现第二子带的静电填充和表征，其能量、填充和自旋轨道耦合强度具有巨大的可调性。高达350%或超过250毫电子伏特的调制是可以实现的，这突出了InSe在可调谐红外和太赫兹源、探测器及调制器方面的前景。
