A quantum dot including a nanoparticle template including a first semiconductor nanocrystal including a Group II-VI compound, a quantum well including a second semiconductor nanocrystal disposed on the nanoparticle template, the second semiconductor nanocrystal including a Group IIIA metal excluding aluminum and a Group V element; and a shell comprising a third semiconductor nanocrystal disposed on the quantum well, the third semiconductor nanocrystal including a Group II-VI compound, wherein the quantum dot does not include cadmium, a band gap energy of the second semiconductor nanocrystal is less than a band gap energy of the first semiconductor nanocrystal, the band gap energy of the second semiconductor nanocrystal is less than a band gap energy of the third semiconductor nanocrystal, and the quantum dot includes an additional metal including an alkali metal, an alkaline earth metal, aluminum, iron, cobalt, nickel, copper, zinc, or a combination thereof.