A quantum dot, including a core including a first semiconductor material that includes indium; and a shell including a second semiconductor material, and disposed on the core, wherein the first semiconductor material and the second semiconductor material are different, wherein the shell has at least two branch portions and a valley portion connecting the at least two branch portions, at least one of the at least two branch portions comprises Zn, Se, and S, and a content of sulfur in the at least one branch portion increases in a direction away from the core.