Figure 6. Band diagrams of the triangle monolayer MoS₂ piezotronic device.

(a) Energy band diagram of the device without bias voltage. Schottky barrier has similar barrier heights at the S and D contacts. (b) Energy band diagram of the device with an external bias. The quasi-Fermi level is raised at the source contact. (c) Negative polarization charges induced on three zigzag edges of MoS₂ under a local isotropic compressive strain, depleting free electrons near the contact interface and increasing the SBHs at both contacts. The asymmetry of band diagram is the result of the bias. (d) Positive polarization charges induced on three zigzag edges of MoS₂ under a local isotropic tensile strain, attracting free electrons near the contact interface and decreasing the SBHs at both contacts. The red arrows represent the directions of polarization. E_F is Fermi level of monolayer MoS₂, E_C is conduction band, E_V is valence band, V_bias is the external bias and Δ is the piezopotential induced the change of barrier height.