STM images of 30-nm-thick In₂Se₃ thin film with post-annealing and rapid quench, showing (a) surface morphology in a large scale of 300 nm × 300 nm; (b) surface morphology in a medium scale of 70 nm × 70 nm, represented by black square in panel (a); (c) surface morphology with a step in small scaled area 42 nm × 30 nm, represented by the black rectangle in panel (b); (d) step height is characterized to be 0.958 nm after correction.