Crystalline and electrical characteristics of C_(60)-doped GaAs films

摘要

C_(60) uniformly doped and 5-doped GaAs layers are grown by migration enhanced epitaxy method. Crystalline and electrical characteristics of the layers are investigated by reflection high energy electron diffraction, X-ray diffraction and capacitance-voltage {C-V) measurements. C_(60) high-concentration doping is found to introduce 2D defects, and X-ray diffraction pole-figure measurements show that the rotational domains appear predominantly on {111 }A plane. This indicates that C_(60) molecules are mainly incorporated on the dangling bonds of Ga atoms due to the high binding energy between C_(60) molecules and Ga atoms. C_(60) uniformly doped GaAs layers show highly resistive characteristics, suggesting that C_(60) molecules cannot be decomposed into isolated C atoms in the GaAs lattice, and they behave as if they were electron traps or strong recombination centers. C-V profiles of Cr-Au/C_(60) 5-doped GaAs Schottky diode suggest that C_(60) molecules in GaAs lattice produce electron traps which can be charged or discharged by applied electrical field.