## 2019年6月14日星期五

### Multiple-scattering effects in Ga K-edge extended x-ray absorption fine structure spectra of GaP, GaAs and GaSb semiconductor compounds

The dependence of Ga K-edge multiple-scattering extended x-ray absorption fine structure (MS-EXAFS) effects on the nearest neighbours in GaP, GaAs and GaSb semiconductor compounds with the zinc blende structure has been comprehensively investigated by considering the coordination environment within the first three shells around the Ga atoms. It is revealed that in the case of GaP with a light element as the first neighbour of the Ga absorber, the MS-EXAFS effects are negligibly weak with respect to the single-scattering (SS) contribution. For GaAs and GaSb compounds with heavier elements as the first neighbour of the Ga absorber, the MS effects become increasingly important and are dominated by a triangular double-scattering path DS2 (\mathrm {Ga}_{0} \to \mathrm {B}_{1} \to \mathrm {B}_{2} \to \mathrm {Ga}_{0} ). The EXAFS contribution of the DS2 path destructively interferes with that of the second shell single-scattering path (SS2), with the amplitude ratio of DS2 to SS2 rising from 7% for GaP to 25 and 70% for GaAs and GaSb, respectively. This indicates that the second shell peak magnitude for these compounds is increasingly damped by the MS effects as the first nearest neighbour goes from P to Sb. Based on these results, we present a generalized and simplified high-shell MS-EXAFS analysis method for compounds with the open structure of zinc blende.

Source:IOPscience

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