TY - JOUR
T1 - High purity isotopically enriched 70Ge and 74Ge single crystals
T2 - Isotope separation, growth, and properties
AU - Itoh, Kohei
AU - Haller, E. E.
AU - Hansen, W. L.
AU - Farmer, J. W.
AU - Ozhogin, V. I.
AU - Rudnev, A.
AU - Tikhomirov, A.
N1 - Funding Information:
We are indebted to J. Beeman for helpful discussions and technical support. This work was supported in part by the United States NSF Center for Particle Astrophysics ADT-8809616 and in part by the United States NASA Contract W17605 through interagency agreement with the United States Department of Energy Contract DE-AC03-76SF00098.
PY - 1993/6
Y1 - 1993/6
N2 - 70 Ge and 74 Ge isotopes were successfully separated from natural Ge and zone purified. Several highly enriched, high purity 70 Ge and 74 Ge single crystals were grown by the vertical Bridgman method. The growth system was designed for reliable growth of low dislocation density, high purity Ge single crystals of very small weight (∼4 g). A 70Ge and a 74Ge crystal were selected for complete characterization. In spite of the large surface to volume ratio of these ingots, both 70Ge and 74Ge crystals contain low electrically active chemical net-impurity concentrations of ~2 X 1012 cm-3, which is two orders of magnitude better than that of 74 Ge crystals previously grown by two different groups.1,2 Isotopic enrichment of the 70Ge and the 74Ge crystals is 96.3% and 96.8%, respectively. The residual donors and acceptors present in both crystals were identified as phosphorus and copper, respectively. In addition, less than 1011cm-3 gallium, aluminum, and indium were found in the 70Ge crystal.
AB - 70 Ge and 74 Ge isotopes were successfully separated from natural Ge and zone purified. Several highly enriched, high purity 70 Ge and 74 Ge single crystals were grown by the vertical Bridgman method. The growth system was designed for reliable growth of low dislocation density, high purity Ge single crystals of very small weight (∼4 g). A 70Ge and a 74Ge crystal were selected for complete characterization. In spite of the large surface to volume ratio of these ingots, both 70Ge and 74Ge crystals contain low electrically active chemical net-impurity concentrations of ~2 X 1012 cm-3, which is two orders of magnitude better than that of 74 Ge crystals previously grown by two different groups.1,2 Isotopic enrichment of the 70Ge and the 74Ge crystals is 96.3% and 96.8%, respectively. The residual donors and acceptors present in both crystals were identified as phosphorus and copper, respectively. In addition, less than 1011cm-3 gallium, aluminum, and indium were found in the 70Ge crystal.
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U2 - 10.1557/JMR.1993.1341
DO - 10.1557/JMR.1993.1341
M3 - Article
AN - SCOPUS:0027608299
VL - 8
SP - 1341
EP - 1347
JO - Journal of Materials Research
JF - Journal of Materials Research
SN - 0884-2914
IS - 6
ER -