Glossary
Glossary
Knudsen effusion Cells are used as evaporator in MBE for materials like Ga, In, Al, As etc.. It is a thermal evaporator with a crucible. The flux of the source is controlled by careful temperature regulation.
A typical effusion cell contains a crucible (made of pyrolytic boron nitride, quartz, tungsten or graphite), heating filaments (often made of metal tantalum), water cooling system, heat shields and orifice shutter.
The original Knudsen type evaporation source is an evaporation cell with small orifice. But, today k-cell is used for large opening effusion sources as well.