Fig. 1: Materials and device characterizations.

a Schematic illustration of the HJ device fabrication process. The external electrical circuit is presented for forward bias and positive gate conditions. b 3D surface topography of the α-In₂Se₃/In₂O₃ HJ FET device measured by AFM. c The flake thickness is found to be ~28 nm, as present in the line profile. After laser treatment, ~4–5 nm thickness reduction with a slight increase in roughness was observed. d Optical image of the fabricated device (scale bar 5 μm). The red dotted area is indicating the selectively laser exposed region. e–g Raman maps for the same device before and after laser expose (scale bar 2 μm). The electrodes are superimposed for better understating. h Raman spectra are presented for the pristine (blue) and laser written (red) regions.