Photo-Hall Effect in Anthracene

The Hall mobility for photogenerated carriers has been measured in anthracene crystals in the temperature range from -40 to 60°C. Two-carrier effects were found to dominate, so that only lower limits could be calculated for the mobility. Near room temperature, the Hall mobility exceeds 50 ${\mathrm{cm}}^2$ ${\mathrm{V}}^{-1\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ for electrons and 30 ${\mathrm{cm}}^2$ ${\mathrm{V}}^{-1\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ for holes, compared with values close to 1 ${\mathrm{cm}}^2$ ${\mathrm{V}}^{-1\mathrm{}}$ ${\sec }^{-1\mathrm{}}$ measured for the drift mobility. The most likely explanation for this difference is a change in transport properties with illumination level. The existence of the anomalous Hall effect predicted by LeBlanc and Friedman could not be verified.