Atomic-level characterisation of the structure of amorphised GaAs utilising EXAFS measurements

Extended X-ray absorption fine structure (EXAFS) analysis has been used to determine the structural parameters of stoichiometric, amorphised GaAs. Relative to a crystalline sample, the nearest-neighbor bond length and Debye-Waller factor both increased for amorphous material. In contrast, the coordination numbers about both Ga and As atoms in the amorphous phase decreased to ∼3.85 atoms from the crystalline value of four. Similar trends were evident for amorphised Ge excluding the coordination number which did not deviate from the crystalline value. The structural parameters of amorphised GaAs and Ge have been discussed in terms of the multi- and mono-elemental nature, respectively, of the two materials