This is a home built “hot filament” CVD reactor. This reactor is equipped with filament heating and independent substrate temperature control. The gas phase activation required for CVD process is achieved by heating the filament (typically, tungsten) up to 2200oC. The substrate temperature can be independently controlled using a ceramic heater capable of attaining temperatures up to 1500oC. The substrate temperature and the filament temperatures are monitored by back-side thermocouple and a pyrometer, respectively. The distance between the filament and the substrate, a crucial parameter, can be adjusted from a few mm to a few cm.