Morphology studies and current-voltage (IV) measurements of C60 thin film diodes in the temperature range of 300–4.2 K are presented. For defined evaporation parameters orientation domains along the growth direction are demonstrated by cross section transmission electron microscopy. From the electrical characterization the fullerene diodes exhibit space charge limited currents which follow a power law dependency. At current densities above 100 mA cm-2 and temperatures below 200 K reversible voltage instabilities (S-shape IV characteristics, negative differential resistance) arise. The instabilities are similar to charge transport effects in amorphous inorganic semiconductors.