Patent ID: 8755240

Claim:
An optical memory device comprising: a substrate; a first barrier layer formed on the substrate; a quantum well layer formed on the first barrier layer, wherein the quantum well layer has an energy band gap which is narrower than an energy band gap of the first barrier layer; a second barrier layer formed on the quantum well layer, wherein the second barrier layer has an energy band gap which is wider than the energy band gap of the quantum well layer, and wherein the energy band gap of the second barrier layer is narrower than the energy band gap of the first barrier layer; a quantum dot layer including a plurality of quantum dots formed on the second barrier layer, wherein the quantum dot layer has an energy band gap which is narrower than the energy band gap of the quantum well layer; and a third barrier layer formed on the quantum dot layer, wherein the third barrier layer has an energy band gap which is wider than the energy band gap of the second barrier layer, and wherein a difference between a conduction band of the second barrier layer and a conduction band of the quantum dot layer is smaller than the energy band gap of the quantum dot layer.