Interlayer Band‐to‐Band Tunneling and Negative Differential Resistance in van der Waals BP/InSe Field‐Effect Transistors

• Published in: Advanced functional materials 2020-04, Vol.30 (15), p.n/a
• Main Authors: Lv, Quanshan, Yan, Faguang, Mori, Nobuya, Zhu, Wenkai, Hu, Ce, Kudrynskyi, Zakhar R., Kovalyuk, Zakhar D., Patanè, Amalia, Wang, Kaiyou
• Format: Article
• Language: English
• Subjects: band‐to‐band tunneling; BP/InSe heterojunctions; Brillouin zones; Computer architecture; Current carriers; Electrical junctions; Energy bands; field‐effect transistors; Heterojunctions; Indium selenides; Interlayers; Materials science; negative differential resistance; Semiconductor devices; Thickness; Thin films; Transistors; Transport properties; Two dimensional materials; Valence band
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201910713

Atomically thin layers of van der Waals (vdW) crystals offer an ideal material platform to realize tunnel field‐effect transistors (TFETs) that exploit the tunneling of charge carriers across the forbidden gap of a vdW heterojunction. This type of device requires a precise energy band alignment of the different layers of the junction to optimize the tunnel current. Among 2D vdW materials, black phosphorus (BP) and indium selenide (InSe) have a Brillouin zone‐centered conduction and valence bands, and a type II band offset, both ideally suited for band‐to‐band tunneling. TFETs based on BP/InSe heterojunctions with diverse electrical transport characteristics are demonstrated: forward rectifying, Zener tunneling, and backward rectifying characteristics are realized in BP/InSe junctions with different thickness of the BP layer or by electrostatic gating of the junction. Electrostatic gating yields a large on/off current ratio of up to 108 and negative differential resistance at low applied voltages (V ≈ 0.2 V). These findings illustrate versatile functionalities of TFETs based on BP and InSe, offering opportunities for applications of these 2D materials beyond the device architectures reported in the current literature. A tunnel field‐effect transistor (TFET) based on a black phosphorus (BP)/indium selenide heterojunction is demonstrated with diverse electrical transport characteristics. Forward rectifying, Zener tunneling, and backward rectifying characteristics are realized in TFETs with different thickness of the BP layer or by electrostatic gating, offering opportunities for applications of these 2D materials in versatile functional devices.