Chapter 23 - Growth and Characterization of Fullerene/GaAs Interfaces and C60-Doped GaAs and AlGaAs Layers

Abstract

C60 molecules have a spherical structure that is much larger than those of Ga and As atoms. Nevertheless, C60 molecules could be adsorbed on specific sites of GaAs surfaces, and these sites are determined by a three-dimensional relationship between C60 molecules and surface reconstruction. This finding implies that C60 molecules are incorporated into GaAs lattices without crystal deterioration, and C60 molecules act as quantum dots with excellent size uniformity. Indeed, we have successfully fabricated C60 uniformly doped GaAs layers by a migration-enhanced epitaxy method, and the layers are confirmed to have a good crystalline quality. C60 uniformly doped GaAs layers show highly resistive characteristics, suggesting that C60 molecules cannot be decomposed into isolated carbon atoms, and they behave as if they were electron traps. Capacitance-voltage characteristics indicate that C60 molecules inside GaAs and AlGaAs lattices produce electron traps that can be charged or discharged by an applied electrical field.