Accession Number : ADA310027

Title :   Arsenic Cluster Engineering.

Descriptive Note : Final rept. 1 Dec 92-31 Mar 96,

Corporate Author : PURDUE UNIV LAFAYETTE IN

Personal Author(s) : Melloch, Michael R.

PDF Url : ADA310027

Report Date : MAY 1996

Pagination or Media Count : 27

Abstract : During this project we have refined our ability to 'arsenic cluster engineer.' We have demonstrated the ability to routinely control the density and diameters of the As clusters using the substrate temperature during MBE to set the excess As concentration and the subsequent coarsening anneal. We have shown that one can vary the incorporation of excess As in GaAs and AlGaAs epilayers by growing at low substrate temperatures using As4 and switching between MBE and MEE modes of growth. Upon anneal, the excess As precipitates preferentially in the GaAs regions of AlGaAs/GaAs heterojunctions due to the lower interfacial energy of an As cluster to GaAs matrix than that of an As cluster to AlGaAs matrix. The excess As can be retained in the AlGaAs regions where it will precipitate with anneal if thin AlAs As-diffusion barriers are used to clad the AlGaAs regions. These ACE tools will be very useful as we further explore the large electro-optic effect we have discovered in these composites.

Descriptors :   *CLUSTERING, *ENGINEERING, *ARSENIC, TEMPERATURE, ANNEALING, LOW TEMPERATURE, ELECTROOPTICS, INTERFACES, GROWTH(GENERAL), GALLIUM ARSENIDES, ALUMINUM GALLIUM ARSENIDES, HETEROJUNCTIONS, SUBSTRATES, LOW ENERGY, BARRIERS, ALUMINUM ARSENIDES, DIFFUSION, PRECIPITATES, MOLECULAR BEAM EPITAXY.

Subject Categories : Inorganic Chemistry
      Physical Chemistry
      Electrooptical and Optoelectronic Devices
      Crystallography
      Electricity and Magnetism
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE