Optical Spectroscopy of Schottky Nanostructures Au/GaAs: Plasmon Resonances and Anisotropy

— The Schottky nanostructures Au/GaAs with Au nanoclusters are prepared by annealing of thin gold films deposited on nitridized GaAs(001) surface. The nanostructures are diagnosed nanoscopically and investigated by optical reflection anisotropy spectroscopy. The Au nanoclusters arrays of two types are found to be formed respectively under and over GaAs surface. The energies of local plasmons of the arrays are detected at 1.6 and 2.15 eV, respectively. The latter plasmons possess in-surface anisotropy which causes in optical anisotropy spectra the intensive resonant feature at energy about 2 eV. The plasmon anisotropy is studied comprehensively, and the results are interpreted theoretically.