Resonant Tunneling between Quantized Subbands in van der Waals Double Quantum Well Structure Based on Few-Layer WSe<sub>2</sub>
Kei Kinoshita, Rai Moriya, Shota Okazaki, Yijin Zhang, Satoru Masubuchi, Kenji Watanabe, Takashi Taniguchi, T. Sasagawa, Tomoki Machida
Abstract
We demonstrate van der Waals double quantum well (vDQW) devices based on few-layer WSe2 quantum wells and a few-layer h-BN tunnel barrier. Due to the strong out-of-plane confinement, an exfoliated WSe2 exhibits quantized subband states at the Γ point in its valence band. Here, we report resonant tunneling and negative differential resistance in vDQW at room temperature owing to momentum- and energy-conserved tunneling between the quantized subbands in each well. Compared to single quantum well (QW) devices with only one QW layer possessing quantized subbands, superior current peak-to-valley ratios were obtained for the DQWs. Our findings suggest a new direction for utilizing few-layer-thick transition metal dichalcogenides in subband QW devices, bridging the gap between two-dimensional materials and state-of-the-art semiconductor QW electronics.