PHOTOCONDUCTIVITY OF ICOSAHEDRAL AL70.5PD21RE8.5 - SEMICONDUCTOR-LIKEBEHAVIOR OF QUASI-CRYSTALS

Using the modulated photocurrent method to measure physical properties in the high-structural-quality single-phase icosahedral quasicrystall ine alloy Al70.5Pd21Re8.5, we observed photocurrent similar to that in semiconductors in quasicrystals. The observed results were in agreeme nt with those obtained br applying our recently developed photoconduct ivity model used for boron-rich semiconductors in which band-to-band p hotoexcitation and photoexcitation from a band to localized states fol lowed by thermal excitation to the conduction hand are both considered . Our results confirm the existence of a pseudogap at the Fermi energy E-F and the tendency of carriers to localize near E-F.