Optical memory device and method of recording/reproducing information by using the same

An optical memory device and a method of recording/reproducing information by using the optical memory device. The optical memory device includes a substrate; a first barrier layer formed on the substrate; a quantum well layer; a second barrier layer; a quantum dot layer; and a third barrier layer. The quantum well layer has an energy band gap which is wider than that of the quantum dot layer, and the second barrier layer has an energy band gap which is wider than that of the quantum well layer, so that electrons in excitons which are generated in the quantum dot layer by light of a certain wavelength are captured by the quantum well layer to record information, and then, recorded information may be erased or reproduced by irradiating light of a certain wavelength to the optical memory device.