A heat sink includes a thermally conductive layer comprising at least one of fullerenes and nanotubes disposed in a polymeric host. The thermally conductive layer may be disposed on a heat sink body, which may be thermally insulating and/or plastic, and may include surface area enhancing heat radiating structures, such as fins, with the thermally conductive layer being disposed over at least the surface area enhancing heat radiating structures. A light emitting diode (LED)-based lamp embodiment includes the heat sink and an LED module including one or more LED devices secured with and in thermal communication with the heat sink. A method embodiment includes forming the heat sink body and disposing the thermally conductive layer on the heat sink body. The disposing may comprise spray coating. An external energy field may be applied during spray coating to impart a non-random orientation to nanotubes in the polymeric host.