Accession Number : ADA311133

Title :   Nucleation and Growth of Semiconductor-Metallic Superlattices.

Descriptive Note : Final rept. 1 Dec 92-30 Nov 95,

Corporate Author : MINNESOTA UNIV MINNEAPOLIS DEPT OF ELECTRICAL ENGINEERING

Personal Author(s) : Cohen, P. I.

PDF Url : ADA311133

Report Date : 30 NOV 1995

Pagination or Media Count : 17

Abstract : An investigation of the nucleation and growth as well as magnetic properties of epitaxial FeAl on AlAs/GaAs(100) is reported. These are the first real space studies of the nucleation, growth and properties of so-called thermodynamically stable films. In-situ RHEED and the first UHV STM measurements were used to characterize the surface. Ex-situ MOKE measurements were used to characterize the magnetic properties. FeAl was found to have an unusual incubation effect over the first 3 bilayers of growth on AlAs. STM images taken at 1 and 3 bilayers examined this effect. After depositing 9 nm and annealing, the films exhibited a 2x2 and/or a 5x5 surface reconstruction. This reconstruction depended upon the anneal temperature and film composition. STM images showed atomic step terraces with step heights roughly corresponding to the height of an FeAl bilayer. Differences were also seen in the surface morphology of the 2-fold and 5-fold surfaces. It was determined that the growth mode was primarily dependent upon growth composition, but had some dependence on the annealed FeAl starting surface. The growth mode changed from monolayer to bilayer closely corresponding to the composition at which FeAl changes from ferromagnetic to non magnetic.

Descriptors :   *METALS, *SUPERLATTICES, *EPITAXIAL GROWTH, *SEMICONDUCTORS, *NUCLEATION, SCANNING, TEMPERATURE, ANNEALING, MAGNETIC PROPERTIES, STABILITY, LAYERS, THERMODYNAMICS, GALLIUM ARSENIDES, MORPHOLOGY, FILMS, MICROSCOPY, SURFACE PROPERTIES, INCUBATION, ALUMINUM ARSENIDES, TUNNELING, ULTRAHIGH VACUUM, INTERMETALLIC COMPOUNDS, IRON ALUMINIDE.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Electrical and Electronic Equipment
      Electricity and Magnetism
      Atomic and Molecular Physics and Spectroscopy
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE