J. Phys. Colloques 47 (1986) C8-423-C8-426
LOCAL STRUCTURE IN InGaAsP QUATERNARY ALLOYSH. OYANAGI1, Y. TAKEDA2, T. MATSUSHITA3, T. ISHIGURO1 et A. SASAKI2
1 Electrotechnical Laboratory, Umezono, Sakuramura, Niiharigun, Ibaraki 305, Japan
2 Department of Electrical Engineering, Kyoto University, Kyoto 606, Japan
3 National Laboratory for High Energy Physics, Ohomachi, Tsukubagun, Ibaraki 305, Japan
The local structure of InGaAsP quaternary alloys epitaxially grown on InP substrates has been studied by EXAFS and near-edge structure. The bimodal distribution of bondlength at both cation (In, Ga) and anion (As, P) sites were confirmed. The bondlengths were found to deviate from the VCA average by 2.4-5.5 % whereas they deviate from those in pure binary compounds by only 0.9-1.6 %. These deviations were found to be constant within 0.4 % over a wide range of composition when the VCA average is kept constant. Two cation species (Ga, In) and anion species (As, P) are expected to be randomly distributed on each sublattices. The average interatomic distance calculated from the weighted sum of bondlengths agrees the VCA average over a wide range of alloy composition. These results imply that lattice relaxation of lattice-matched quaternary alloys can be realized by only bond-bending.