A New Opportunity for 2D van der Waals Heterostructures: Making Steep‐Slope Transistors

Abstract

The use of a foreign metallic cold source (CS) has recently been proposed as a promising approach toward the steep-slope field-effect-transistor (FET). In addition to the selection of source material with desired density of states-energy relation (D(E)), engineering the source: channel interface for gate-tunable channel-barrier is crucial to a CS-FET. However, conventional metal: semiconductor (MS)-interfaces generally suffer from strong Fermi-level-pinning due to the inevitable chemical disorder and defect-induced gap states, precluding the gate-tunability of the barriers. By comprehensive materials and device modeling at the atomic-scale, we report that the two-dimensional (2D)-van der Waals (vdW)-MS-interfaces, with their atomic sharpness and cleanness, can be considered as general ingredients for CS-FETs. As test cases, InSe-based n-type FETs are studied. It is found that graphene can be spontaneously p-type doped along with slightly opened bandgap around the Dirac-point by interfacing with InSe, resulting in super-exponentially decaying hot carrier density with increasing n-type channel-barrier. Moreover, the D(E) relations suggest that 2Dtransition-metal-dichalcogenides and 2D-transition-metal-carbides are rich libraries of CS materials. Both graphene and H-TaTe2 CSs lead to subthreshold swing below 60 mV/decade. This work broadens the application potentials of 2D-vdW-MSheterostructures and serves as a springboard for more studies on low-power electronics based on 2D materials.

Low‐Power Complementary Inverter with Negative Capacitance 2D Semiconductor Transistors

“…It is highly desirable to further reduce power consumption by integrating 2D semiconductor channels and NC gate stack to form NCFETs. [ 2,13,15–18 ]…”

Atomically thin photoanode of InSe/graphene heterostructure

“…Such 2D materials have been demonstrated to have a direct band gap in the visible range, strong light absorption efficiency, and unique light-matter interactions 12,13 . Importantly, the possibility of assembling various 2D crystals into heterostructures offers another degree of freedom to adjust the band structure of these materials [14][15][16][17] . The resulting devices have been demonstrated to have tunable band gaps and elongated photo electron-hole pair lifetimes, which properties are essential for high-efficiency PEC water splitting [18][19][20] .…”

Nanodevices engineering and spin transport properties of MnBi2Te4 monolayer

“…Several intrinsically magnetic 2D materials have attracted considerable attention in recent years, including VX 2 (X = S, Se, Te) [3][4][5][6][7][8][9] , CrGeTe 3 [10][11][12][13] , Fe 3 GeTe 2 [14][15][16][17] , and CrX 3 (X = Cl, Br, I) [18][19][20][21][22][23][24] . Furthermore, the discovery of MnBi 2 Te 4 (MBT) represents another step forward, as it integrates topological feature and alternating ferromagnetic or antiferromagnetic ordering in a single system 1 .…”