Van der Waals Heterostructures for Orbital Gating in Photo-transistors and Electronic Spectroscopy
일 시 : 2023년 04월 26일 수요일 16:30
연 사 : 양 희 준 교수 (KAIST 물리학과)
장 소 : 자연과학관 B117호
HOST : 박 문 집 교수님
초 록
Each atomic layer in van der Waals heterostructures possesses a distinct electronic band structure that can be manipulated for unique device operations. The subtle but critical band coupling between the atomic layers, varied by the momentum (valley) of electrons and external electric fields in device operation, has not yet been presented or applied to designing original devices with the full potential of van der Waals heterostructures.
In this talk, I will introduce interlayer coupling spectroscopy at the device-scale based on the negligible quantum capacitance of two-dimensional semiconductors in lattice-orientation-tuned, resonant tunneling transistors (Figure below). The effective band structures of the mono-, bi-, and quadrilayer of MoS2 and WSe2, modulated by the orientation- and external electric field-dependent interlayer coupling in device operations, could be demonstrated by the new conceptual spectroscopy overcoming the limitations of the former optical, photoemission, and tunneling spectroscopy [1]. Based on the vertical heterojunction, single-defect resonant transistors [2], and novel orbital-gating phototransistors [3] could be developed.
[1] Resonant tunneling spectroscopy to probe the giant Stark effect in atomically-thin materials, Advanced Materials 32, 1906942 (2020)
[2] Robust Quantum Oscillation of Dirac Fermions in a Single-Defect Resonant Transistor, ACS Nano 15, 20013 (2021)
[3] Orbital gating driven by giant Stark effect in tunneling phototransistors, Advanced Materials 34, 2106625 (2022)