Figure 1. Structure of films.

(a) Crystal structure of pure SnS. (b) Out-of-plane (top panel) and in-plane (bottom panel) synchronous scan XRD patterns of film with x_f = 0.5 grown at 300 °C and 5 Pa. (c) Pb content (x_t for target, x_f for thin films) as a function of pressure, substrate temperature, and x_t. The half-filled symbols indicate the targets, the closed circles the orthorhombic phase crystalline films, and the open symbols amorphous films. (d) 400 out-of-plane XRD diffraction peaks of the films grown at 300 °C with various x_f values. (e) Lattice parameters (a, b, c) of films as a function of x_f. The closed circles indicate those obtained with the thin films, the solid lines are those of bulk (Sn_1–xPb_x)S taken from ref. 25, and the open symbols are the calculation results obtained by DFT in this work. The dashed straight lines are guides for eyes. (f) (Sn_1-xPb_x)S supercell model used for DFT calculations. The black line box draws the (Sn_16–nPb_n)S₁₆ supercell model used for calculating the lattice parameters in Fig. 1e. The blue line box draws the (Sn₁₆Pb₁₆)S₃₂ supercell model used for defect calculations in Fig. 4, where the intrinsic defect models examined in this study are indicated also in the figure.