High purity isotopically enriched [sup 70]Ge and [sup 74]Ge single crystals: Isotope separation, growth, and properties

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · Journal of Materials Research; (United States)

DOI:https://doi.org/10.1557/JMR.1993.1341· OSTI ID:6457689

Itoh, K ^[1]; Hansen, W L ^[2]; Haller, E E ^[1]; Farmer, J W ^[3]; Ozhogin, V I; Rudnev, A; Tikhomirov, A ^[4]

---

1. University of California at Berkeley ( ) Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
2. Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
3. University of Missouri, Columbia, Missouri 65211 (United States)
4. Russian Science Center Kurchatov Institute,'' 123182 Moscow (Russian Federation)

[sup 70]Ge and [sup 74]Ge isotopes were successfully separated from natural Ge and zone purified. Several highly enriched, high purity [sup 70]Ge and [sup 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 ([similar to]4g). A [sup 70]Ge and a [sup 74]Ge crystal were selected for complete characterization. In spite of the large surface to volume ratio of these ingots, both [sup 70]Ge and [sup 74]Ge crystals contain low electrically active chemical net-impurity concentrations of [similar to]2[times]10[sup 12] cm[sup [minus]3], which is two orders of magnitude better than that of [sup 74]Ge crystals previously grown by two different groups.[sup 1,2] Isotopic enrichment of the [sup 70]Ge and the [sup 74]Ge 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 10[sup 11] cm[sup [minus]3] gallium, aluminum, and indium were found in the [sup 70]Ge crystal.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6457689
• Journal Information: Journal of Materials Research; (United States), Journal Name: Journal of Materials Research; (United States) Vol. 8:6; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
BRIDGMAN METHOD
COPPER
CRYSTAL GROWTH
CRYSTAL GROWTH METHODS
CRYSTALS
ELEMENTS
EVEN-EVEN NUCLEI
GERMANIUM 70
GERMANIUM 74
GERMANIUM ISOTOPES
IMPURITIES
INTERMEDIATE MASS NUCLEI
ISOTOPE SEPARATION
ISOTOPES
METALS
MONOCRYSTALS
NONMETALS
NUCLEI
PHOSPHORUS
PROCESSING
REFINING
SEPARATION PROCESSES
STABLE ISOTOPES
TRANSITION ELEMENTS
ZONE REFINING