COMPACT SUPERSONIC MOLECULAR-BEAM SOURCE WITH A LIQUID-NITROGEN TRAP

A compact supersonic molecular beam source was developed that has a liquid nitrogen trap to cryogenically pump the gas and is small enough in size to install in conventional molecular beam epitaxy (MBE) systems. With the source, well-collimated molecular beams of N2O and NO2 whose flux densities are approximately 10(16) molecules cm-2 S-1 are generated. The effectiveness of the source was proved in the preparation of oxide superconducting thin films by MBE with an NO2 beam where as-grown superconducting films were obtained in high vacuum of less-than-or-equal-to 10(-5) Pa.