Preparation of Single-Crystal Isotopically Enriched 70Ge by a Hydride Method.

Single-crystal ⁷⁰Ge germanium with high isotopic and chemical purity has been prepared by a hydride method. Germanium isotopes have been separated by centrifugation with the use of monogermane as a starting volatile substance. Isotopically enriched polycrystalline ⁷⁰Ge has been prepared by pyrolyzing ⁷⁰GeH₄ monogermane. A ⁷⁰Ge single crystal has been grown by the Czochralski technique. The resultant material has p-type conductivity and intrinsic resistivity at room temperature. The concentration of elemental impurities is under 10^–6 to 10^–5 wt %. The isotopic purity of the ⁷⁰Ge single crystal is 99.926 at % and it contains a record low concentration of the odd isotope ⁷³Ge: 0.00007 at %. [ABSTRACT FROM AUTHOR]