Facile Synthesis of Carbon Film with High Carrier Concentration Using Coal Tar and the Application in Joule Heating

The excellent electrical, thermal, and mechanical properties of carbon films make them promising for application in functional devices. As the byproduct of the coking industry with low cost and large quantity, coal tar can be an alternative feedstock for preparing high-performance carbon films. This work adopts the negative-pressure chemical vapor deposition (NPCVD) approach to prepare thin films on a glass substrate with tunable electrical properties and thickness using coal tar as carbon source. The sheet resistance of as-prepared carbon films can be adjusted within 3 orders of magnitude due to its high carrier density (up to 2.1 × 1022/cm3). As potential Joule heater, carbon film is characterized by fast heating rate (up to 12.5 °C/s) and high temperature (up to 300 °C at 40 V in 24 s). The thickness and sp2 cluster size affect the carrier density and carrier mobility of carbon film. These results verify the feasibility of using coal tar to synthesis high-performance carbon films suitable for electronic applications.