Accurate measurement of atomic beam flux by pseudo-double-beam atomic absorption spectroscopy for growth of thin-film oxide superconductors

We report the use of pseudo-double-beam atomic absorption spectroscopy to make very accurate (0.1%–1%) measurements of the beam flux from Knudsen effusion cells in a molecular beam epitaxy system. This system has been used to grow Bi–Sr–Ca–Cu–O–based superconducting thin films and heterostructures in an atomic-layer-by-layer fashion. The resulting material displays excellent crystallographic and transport properties. Atomic absorption measurement of beam fluxes may also be of benefit for other materials systems, such as InGaAs/InP.