Initial evaluation of a valved Te source for MBE growth of HgCdTe

Initial results using a valved Te source for molecular beam epitaxial growt h of Hg1-xCdxTe are described. Unlike the case for a conventional Knudsen e ffusion cell where the flux is controlled primarily by temperature, flux fr om the valved source is controlled primarily by a variable orifice capable of good closure so that the cell temperature can be fixed at the operating temperature. Operating characteristics of the source are described, and inc lude being able to nearly instantaneously change the flux magnitude at will . Using the source for HgCdTe growth has resulted in promising composition reproducibility improvement in initial growth runs.