Negative Differential Resistance Device with High Peak-to-Valley Ratio Realized by Subband Resonant Tunneling of Γ‑Valley Carriers in WSe2/h‑BN/WSe2 Junctions

• Published in: ACS nano 2024-10, Vol.18 (42), p.28968-28976
• Main Authors: Kinoshita, Kei, Moriya, Rai, Kawasaki, Seiya, Okazaki, Shota, Onodera, Momoko, Zhang, Yijin, Watanabe, Kenji, Taniguchi, Takashi, Sasagawa, Takao, Machida, Tomoki
• Format: Article
• Language: English
• ISSN: 1936-0851; 1936-086X; 1936-086X
• DOI: 10.1021/acsnano.4c09569

Resonant tunneling diodes (RTDs) are a core technology in III–V semiconductor devices. The realization of high-performance RTD using two-dimensional (2D) materials has been long awaited, but it has yet to be accomplished. To this end, we investigate a range of WSe2/h-BN/WSe2 RTD devices by varying the number of layers of source and drain WSe2. The highest peak-to-valley ratio (PVR) is demonstrated in the three-layer (3L) WSe2/h-BN/1-layer (1L) WSe2 structure. The observed PVR values of 63.6 at 2 K and 16.2 at 300 K are the highest among the 2D material-based RTDs reported to date. Our results indicate the two key conditions to achieve high PVR: (1) resonant tunneling should occur between the Γ-point bands of the source and drain electrodes, and (2) the Γ-point bands contributing to the resonant tunneling should be energetically separated from the other bands. Our results provide an important step to outperform III–V semiconductor RTDs with 2D material-based RTDs.