Transition metal dichalcogenides (TMDs) are layered compounds which display a wide range of electronic ground states, ranging from superconductivity, to semi-metallicity to wide gap semiconducting behavior. Here, we will discuss our previous studies on exfoliated semiconducting compounds, which indicate, for example, that field-effect transistors (FETs) based on few atomic layers of these materials (i.e. MoSe₂ or WSe₂), and their heterostructures, display a great potential for photo-sensing [1,2,3] and photovoltaic applications [4], since these compounds are prone to a particularly strong interaction with light. Other compounds like ReS₂ display a gate-voltage controlled metal to insulator transition at room temperature, with the metallic state surviving down to quite low temperatures [5]. Ambipolar FETs based on ReSe₂ show promise as voltage inverters [6]. Meanwhile, we find through a detailed structural analysis reveals that it is possible to produce solid solutions of, for example, Mo_1-xW_xTe₂ which leads to a sharp phase-boundary between the semiconducting 2H- and the semi-metallic T_d- phases [7]. Based on a series of recent theoretical predictions, we argue that it might be possible to tune this phase-boundary through a gate voltage perhaps leading to phase change memory elements. Furthermore, given that 2H-MoTe₂ display a band gap comparable to Si (≈ 1 eV) and that its semi-metallic counterpart is claimed to display topological properties, we argue that it might possible to produce optoelectronic components characterized by low dissipation if one is capable to harvest the topological nature of its semi-metallic phase.

[1] N. Pradhan et al., ACS Appl. Mater. & Interfaces 7, 22, 12080 (2015).

[2] N. Pradhan et al., 2D Mater. 3, 041004 (2016).

[3] N.R. Pradhan et al., Adv. Electron. Mater. 1, 10, 1500215 (2015)

[4] S. Memaran  et al., Nano Lett. 15, 7532 (2015)

[5] N. Pradhan et al., Nano Lett. 15, 8377 (2015)

[6] N. R. Pradhan (unpublished)

[7] D. Rhodes et al., Nano Lett. 17, 1616 (2017)