Disclosed is a method for growing a thin film, which includes modifying a surface grain size and surface roughness on a thin film to improve the mobility of a carrier and a light scattering effect. The method for growing a thin film includes: forming nuclei of grains having various grain orientations on a substrate; causing first grains having a first specific grain orientation to grow predominantly among the grains having various grain orientations, thereby forming a first preferred texture comprised of the predominantly grown first grains; and then causing second grains having a second grain orientation to grow predominantly, thereby forming a second preferred texture comprised of the predominantly grown second grains, wherein the surface grain size of each of the second grains forming the second texture is larger than that of each of the first grains forming the first texture.