(a) Schematic diagram of the proposed slanted NCH array textured silicon thin film layer with an Ag back-reflector located under the bottom of it. (b) The top view of the slanted silicon NCH array. S_ellipse represents the area of ellipse, while S_cell represents the area of silicon unit cell surface. The filling factor FF = S_ellipse/S_cell. a and b are the lattice constants of the slanted NCH along the x and y directions, respectively. Panels (c) and (d) show the side views of the slanted silicon NCH before and after removing the excrescent part. θ and ϕ are the taper angle and tilt angle of the NCH, respectively. The black dashed line is the height of the NCH while O is the middle point of the height. h is the height of the silicon unit cell.