Accession Number : AD0714986

Title :   Electron Paramagnetic Resonance Study of Clean and Oxygen Exposed Surfaces of GaAs, AlSb and Other III-V Compounds.

Descriptive Note : Annual rept. no. 2, Aug 69-Jul 70,

Corporate Author : NEW SOUTH WALES UNIV KENSINGTON (AUSTRALIA) DEPT OF PHYSICS

Personal Author(s) : Haneman,D.

Report Date : OCT 1970

Pagination or Media Count : 59

Abstract : Information has been obtained about the surface wave functions, electron states, oxygen adsorption sites and adsorption modes on clean (110) surfaces of GaAs and related semiconductors. The principal method utilised electron paramagnetic resonance measurements of samples crushed and measured in ultra high vacuum. It was shown that the signal is caused by O2(-) ions formed on the GaAs surface. The signal is not reversible to pumping but disappears on warming to -100C and forms again only after re-exposure to oxygen at 77K. About 5% of the wave function of the unpaired electron on the 02(-) molecule ion is localised on the Al atom. The unfilled (dangling) orbital of this surface atom is found to be over 90% p type. This provides apparently the first experimental determination of a clean semiconductor surface wave function. A model of the (110) surface of a III-V compound semiconductor is proposed and the adsorption site of the O2(-) ion is specified. A solution for the g tensor has been obtained for the case of the low symmetry pertaining to the surface, and surface electric field gradients have been deduced. (Author)

Descriptors :   (*OXYGEN, *ADSORPTION), (*GALLIUM ARSENIDES, ADSORPTION), MOLECULAR ORBITALS, SURFACE PROPERTIES, ANTIMONY ALLOYS, ALUMINUM COMPOUNDS, PARAMAGNETIC RESONANCE

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE