The evaporation source using electric heating can be used to deposit most organic and inorganic thin films, among which the resistance Joule method is the most common.
Thermal evaporation is one of the simplest of Physical Vapor Deposition (PVD) used to deposit material. The materials (metal, organic materials...) are placed in a resistive heat source in vacuum environment to evaporate directly to the substrate, where they condense back to a solid state form a thin film. Thermal evaporation offers faster evaporation rates than sputtering. However, it is limited to size of boat or crucible to contain the material and difficult to control of the evaporation rate.
This method is commonly used for depositing electrodes, single layer of material or co-evaporation materials by controlling many resistive heat sources simultaneously with small scale.