Modulated photocurrent measurements on an Al–Pd–Re icosahedral quasicrystal

Modulated photocurrent measurements, originally developed for analyzing the electronic states of semiconductors have been performed on an Al–Pd–Re quasicrystal having high electrical resistivity using two kinds of lasers with different excitation energies. No noticeable difference has been found in the phase shift between the two excitation energies. The data of the amplitude and phase shift of modulated photocurrent can be explained well by a simple model in which only the two processes, carrier generation and recombination, are involved. The recombination time is by about six orders larger than those reported for conventional semiconductors. The results obtained are discussed in terms of electron density of states and energy dependence of carrier mobility.