Integrated digital inverters based on two-dimensional anisotropic ReS2 field-effect transistors

Abstract

Semiconducting two-dimensional transition metal dichalcogenides are emerging as top candidates for post-silicon electronics. While most of them exhibit isotropic behaviour, lowering the lattice symmetry could induce anisotropic properties, which are both scientifically interesting and potentially useful. Here we present atomically thin rhenium disulfide (ReS2) flakes with unique distorted 1T structure, which exhibit in-plane anisotropic properties. We fabricated monolayer and few-layer ReS2 field-effect transistors, which exhibit competitive performance with large current on/off ratios (∼107) and low subthreshold swings (100 mV per decade). The observed anisotropic ratio along two principle axes reaches 3.1, which is the highest among all known two-dimensional semiconducting materials. Furthermore, we successfully demonstrated an integrated digital inverter with good performance by utilizing two ReS2 anisotropic field-effect transistors, suggesting the promising implementation of large-scale two-dimensional logic circuits. Our results underscore the unique properties of two-dimensional semiconducting materials with low crystal symmetry for future electronic applications.

Electronic and Optoelectronic Applications Based on 2D Novel Anisotropic Transition Metal Dichalcogenides

“…Liu et al observed that the anisotropic ReS 2 ‐based FET under a fixed source–drain bias voltage of 100 mV had a large on/off ratio of 10 7 and low subthreshold swings of 100 mV dec −1 (Figure 6g), when the back gate was swept from −50 to 50 V. The anisotropic mobility ratio µm ax /µm in along two principle axes of this device is 3.1, which is better than that of a device containing few‐layer black phosphorus (Figure 6h) 27, 41. The direction of lowest mobility (0° or 180°) was defined as the reference direction, and the highest mobility of 15.4 cm 2 V −1 s −1 was measured in a six‐layer device in the 120° (or 300°) direction (Figure 6i) 67…”

“…The distance between these dimerized Re atoms can be even shorter than that in rhenium single crystals97; thus, the total energy and symmetry of the system are reduced 40. This is a major origin of the strong anisotropic properties of ReSe 2 and ReS 2 validated by Liu et al67 The in‐plane anisotropic properties of monolayer and few‐layered ReS 2 are shown in Figure 1c, ReS 2 has two principal axes, ( a axis, 118.97°; b axis, 61.03°). In accordance with the angles of the a and b axes, a quadrilateral shape with an angle of ≈60° or 120° is observed in thin, exfoliated ReS 2 , and the large anisotropic ratio of mobility of ReS 2 along the two axes (up to 3.1) is the highest of all studied layered 2D materials.…”

“…d) Band structure of monolayer, trilayer, and five‐layer ReS 2 . Reproduced with permission 67. Copyright 2015, the authors, published under CC‐BY‐4.0 license.…”

Booming Development of Group IV–VI Semiconductors: Fresh Blood of 2D Family

“…and group III–VI nanomaterials (InSe,38, 39, 40, 41, 42 GaSe,43, 44, 45, 46, 47, 48 etc.) have been extensively investigated in many fields including photodetectors,49, 50, 51, 52, 53, 54, 55, 56, 57, 58 gas sensors,59, 60 field effect transistors (FETs),38, 61, 62, 63, 64, 65 and flexible devices 66, 67, 68…”

Identifying light impurities in transition metal dichalcogenides: the local vibrational modes of S and O in ReSe2 and MoSe2

“…[2][3][4] The class of van der Waals layered semiconductors with in-plane anisotropy is a topic of great current interest and, besides ReS 2 and ReSe 2 , it includes black phosphorus, [5][6][7] GeS, 8 transition metal trichalcogenides 9 and Sb 2 Se 3 . 10 Proposed applications of ReX 2 (X = S, Se) include plasmonic materials, 11 polarization-sensitive photodetectors with high sensitivity, [12][13][14][15] inverters, 16 catalytic devices, 17,18 and few-layer field effect 19,20 or heterojunction 21 transistor structures. The anisotropy of the ReX 2 compounds arises because, instead of adopting the octahedral (2H) or trigonal (1T) polymorphs typical of TMDs, they undergo a distortion to form a trigonal 1T′ polymorph.…”