TITLE : Van der Waals Hetero-structures for Orbital Gating in Photo-transistors and Electronic Spectroscopies


Each atomic layer in van der Waals hetero-structures 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 hetero- structures. 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 1.). The effective band structures of the mono-, bi-, and quadri-layer 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 hetero-junction, single- defect resonant transistors [2], and novel orbital-gating phototransistors [3] could be developed.


Joining Link: events/SPS Seminar_HeejunYang-April11-2023..pdf

Speaker: Prof. Heejun Yang

Venue: Online

Date and Time: April 11th, 2023, 12 pm