[TuA1] 2D Materials: Emergent Device Applications

9:30 AM - 9:45 AM JST(12:30 AM - 12:45 AM UTC)

[TuA1-03] Cascade Resonant Tunneling in van der Waals Triple Quantum Well Devices

〇Rai Moriya¹, Kei Kinoshita¹, Arisa Nishimura¹, Mika Ito¹, Momoko Onodera¹, Shota Okazaki², Kenji Watanabe³, Takashi Taniguchi³, Takao Sasagawa², Tomoki Machida¹ (1. The Univ. of Tokyo (Japan), 2. Inst. of Sci. Tokyo (Japan), 3. NIMS (Japan))

While epitaxial semiconductor superlattices have long provided the foundation for groundbreaking optoelectronic devices, the emergence of van der Waals (vdW) heterostructures offers a new frontier for quantum-well (QW) engineering with atomic precision. Here, we demonstrate a vertical triple-quantum-well (TQW) device constructed from a trilayer (3L) WSe₂/h-BN/3L-WSe₂/h-BN/3L-WSe₂ stack. By utilizing the discrete subbands of 3L-WSe₂ as quantum wells and few-layer h-BN as tunnel barriers, we realize a cascade resonant tunneling. Upon the application of a junction bias, the current-voltage (I−V) characteristics exhibit five distinct resonant tunneling peaks, a significant expansion from the three peaks observed in standard double-well structures. This unique transport characteristic arises from the cascade resonant tunneling through successive junctions, where a slight asymmetry in barrier resistance prevents the simultaneous coincidence of resonance, thereby resolving individual tunneling events. This sophisticated vdW-QW technology highlights the potential of multi-stage vdW heterostructures for high-performance multi-valued logic and next-generation high-frequency device applications.