A light emission device includes first and second substrates opposing each other to form a vacuum vessel, an electron emission unit located on the first substrate, a light emission unit located on the second substrate and emitting visible light in response to electrons emitted from the electron emission unit, and a heat dissipating sheet located on an outer surface of the second substrate. The heat dissipating sheet includes carbon nanotubes. A display device includes the light emission device, and a panel assembly located in front of the light emission device to transmit therethrough the light emitted from the light emission device to display images.