Figure 1: Schematic illustration, structural and electrical characteristics and band diagrams of GaN–Al2O3–MoS2 vertical devices.
From: Electric-field-induced strong enhancement of electroluminescence in multilayer molybdenum disulfide
(a) A schematic of the three-dimensional view of the vertically stacked device. (b) A schematic of the cross-sectional view of the device. (c) An optical image of a GaN–Al2O3–MoS2 vertical device. The dashed line highlights the area with Al2O3 layer and bare GaN surface. Scale bar, 4 μm. (d) A cross-sectional high-resolution transmission electron microscope (TEM) image of the interfaces across the GaN substrate, Al2O3 and MoS2 flake vertical stack. The layer number of the MoS2 flake is 14. (e) The ideal band diagram of the vertical heterostructure at zero bias. The dashed lines indicate the position of Fermi levels. At zero bias, the bottom of the conduction band and the top of the valence band of MoS2 fall within the forbidden bandgap of GaN. (f) The ideal band diagram of the vertical heterostructure under forward bias. (g) The ideal band diagram of the heterostructure under reverse bias. (h) Current versus bias voltage characteristic of a vertically stacked device.
