Low temperature carrier transport properties in isotopically controlled germanium

Thesis/Dissertation · Thu Dec 01 04:00:00 EST 1994

DOI:https://doi.org/10.2172/29414· OSTI ID:29414

Itoh, Kohei ^[1]

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1. Univ. of California, Berkeley, CA (United States)

Investigations of electronic and optical properties of semiconductors often require specimens with extremely homogeneous dopant distributions and precisely controlled net-carrier concentrations and compensation ratios. The previous difficulties in fabricating such samples are overcome as reported in this thesis by growing high-purity Ge single crystals of controlled ⁷⁵Ge and ⁷⁰Ge isotopic compositions, and doping these crystals by the neutron transmutation doping (NTD) technique. The resulting net-impurity concentrations and the compensation ratios are precisely determined by the thermal neutron fluence and the [⁷⁴Ge]/[⁷⁰Ge] ratios of the starting Ge materials, respectively. This method also guarantees unprecedented doping uniformity. Using such samples the authors have conducted four types of electron (hole) transport studies probing the nature of (1) free carrier scattering by neutral impurities, (2) free carrier scattering by ionized impurities, (3) low temperature hopping conduction, and (4) free carrier transport in samples close to the metal-insulator transition.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE; National Science Foundation (NSF)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 29414
• Report Number(s): LBL--36683; ON: DE95008489
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
36 MATERIALS SCIENCE
CHEMICAL PREPARATION
CRYSTAL DOPING
ELECTRON TRANSFER
GERMANIUM