J. Phys. Colloques 47 (1986) C8-901-C8-904
THE STRUCTURAL ENVIRONMENT OF Te DOPANTS IN GaAs USING EXAFS IN FLUORESCENCE MODEG.N. GREAVES1, P.J. HALFPENNY2, G.M. LAMBLE3 et K.J. ROBERTS3
1 SERC Daresbury Laboratory, GB-Warrington WA4 4AD, Great-Britain
2 Department of Engineering Materials, University of Southampton, GB-Southampton S09 5NH, Great-Britain
3 Department of Pure and Applied Chemistry, University of Strathclyde, GB-Glasgow G1 1XL, Great-Britain
The local co-ordination of 'grown-in' Te in GaAs has been determined by FLEXAFS measurements. At carrier concentrations of 8 x 1018 cm-3 considerable dilation of the first co-ordination sphere around the dopant takes place, with appreciable contraction of the second co-ordination sphere. The first, second and third nearest neighbour distances were found to be 2.58 (± 0.02) Å, 3.52 (± 0.05) Å and 4.58 (± 0.1) Å, respectively. These are discussed in terms of various models which have been proposed for group VI dopants in GaAs.