Abstract: Solid C₇₀/GaAs contacts were made by vacuum deposition of solid C₇₀ film on the n type and p typeepitaxial GaAs （100） substrates and their electrical properties were studied. It was found that these two kinds of contacts are strongly rectifying heterojunctions. The rectification ratio was higher than 10⁶ and 10⁴ for the C₇₀/n-GaAs and C₇₀/p-GaAs contacts at a bias of ±1V, respectively. At a fixed forward voltage, the current is an exponential function of reciprocal temperature, from which the effective barrier height was determined to be 0.784 eV and 0.531 eV for the C₇₀/n-GaAsand C₇₀/p-GaAs contacts, respectively. One electron trap, E（0.640 eV）,and three hole traps, H₃ （0.822 eV）, H₄ （1.155 eV） and H₅ （0.856 eV ）,were observed at and near the solid C₇₀/GaAs interface by the deep level transient spectroscopy （DLTS）and C-t technique.