Fig. 1: Device schematic and HAADF-STEM and elemental analysis of device interface.

a Schematic of the MnAl2S4/MoS2 2D FET. b A top-view optical image of the device taken by an optical microscope. The yellow rectangle indicates the location of the FIB cut, as shown in (c) for the HAADF-STEM, EDS, and TEM analyses. d The HAADF-STEM of the MnAl2S4/MoS2 interface. e The HAADF-STEM of the vertically stacked MnAl2S4/MoS2/Ni/Cr heterostructure on a SiO2/Si substrate from the area labeled in the red rectangle, and the corresponding EDS elemental map shows the distribution of Mn, Al, S, Mo, S, Ni, and Cr.