Accession Number : ADA292521

Title :   Electronic Properties of Low-Temperature Grown III/V Thin Films.

Descriptive Note : Final technical rept. 1 Jul 91-30 Jun 94,

Corporate Author : CALIFORNIA UNIV BERKELEY

Personal Author(s) : Weber, Eicke

PDF Url : ADA292521

Report Date : 05 DEC 1994

Pagination or Media Count : 17

Abstract : Our study of LT GaAs in the previous contract is furthered by: (1) employing several novel techniques to investigate the defects present and the transport mechanism in LT GaAs. (2) expanding to other LT-III/V compounds and (3) exploring the unique properties of these LT semiconductors for device applications. Photocurrent spectroscopy of annealed LT GaAs gives clear evidence of substantial presence of As(sub Ga) defects in the material. The 'internal photoemission' spectrum is actually found to be due to photoexcitation from As(sub Ga) defects. Magnetic circular dichroism and near-infrared absorption provide sensitive and quantitative measurements of the concentration of the As(sub Ga) defects in both neutral and positively charged states. A systematical study of materials grown and annealed at different temperatures shows that As(sub Ga) defects can account for the pinning of Fermi energy and play a dominant role in the materials. Nuclear magnetic resonance has started to be used to study LT GaAs. Although the study is in its early stage, it has been demonstrated that by using a spin echo technique it is possible to obtain characteristic responses from As in perfect sites and defective sites. in contrast to LT GaAs. LT lnP was found to be highly conductive. jg

Descriptors :   *ELECTRONICS, *LOW TEMPERATURE, *THIN FILMS, *DEFECTS(MATERIALS), *PHOTOELECTRIC EMISSION, *GROUP III COMPOUNDS, *GROUP IV COMPOUNDS, *GROUP V COMPOUNDS, MEASUREMENT, OPTICS, ANNEALING, MAGNETIC FIELDS, NUCLEAR MAGNETIC RESONANCE, DETECTION, SPECTROSCOPY, MATERIALS, ELECTROMAGNETIC PROPERTIES, GALLIUM ARSENIDES, SITES, ENERGY, SEMICONDUCTORS, SENSITIVITY, FERMI SURFACES, MAGNETIC RESONANCE, TRANSPORT PROPERTIES, SPECTRA, ECHOES, INTERNAL, SPINNING(MOTION), ABSORPTION, ELECTRIC CURRENT, NEAR INFRARED RADIATION, CIRCULAR, DICHROISM, PHOTOELECTRICITY.

Subject Categories : Solid State Physics
      Inorganic Chemistry
      Physical Chemistry
      Electrical and Electronic Equipment
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE