Graphene-boron nitride-transition metal dichalcogenides heterostructure based MISFET

Stacking of 2D materials has opened new dimensions in the area of Nano-electronics as both optical and electronic properties of the material change significantly by altering number of layers stacked and materials stacked. A vander waal's (vdWH) heterostructure based metal insulator semiconductor field effect transistor (MISFET) with various channel materials like MoS₂, MoSe₂ and WS₂ is investigated to assess the differences in electronic properties at both material and device levels. The results suggest that amongst all transition metal dichalcogenides (TMDs) channel materials considered, WS₂ has lowest effective mass (for both electron and hole) and highest I_dsat (saturation current) ∼9.216 × 10⁻⁵ Å/ $\mu$ m which suggests the use of WS₂ in making high performance Field Effect Transistors. However, because bulk WS₂ is an indirect bandgap material, it is unsuitable for the fabrication of optical devices. This limitation is addressed by using monolayer WS₂, which possesses a direct bandgap. The values of I_dsat for MoS₂ and MoSe₂ based devices are obtained as ∼4.37 × 10⁻⁵ A/ $\mu$ m and ∼2.323 × 10⁻⁵ A/ $\mu$ m. Furthermore, WS₂ as channel material has lowest threshold voltage ∼1 V in comparison to ∼1.1 V and ∼1.2 V for MoS₂ and MoSe₂ based transistors.