EXAFS Characterization of Amorphous GaAs

摘要

The structural parameters of stoichiometric, amorphous GaAs have been determined with extended x-ray absorption fine structure (EXAFS) measurements performed in transmission mode at 10K. Amorphous GaAs samples were fabricated with a combination of epitaxial growth, ion implantation and selective chemical etching. Relative to a crystaline 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 approx 3.85 atoms from the crystalline value of our. All structural parameters were independent of implantation conditions and as a consequence, were considered representative of intrinsic, amorphous GaAs as opposed to an implantation-induced extrinsic structure.