Direct-Current Measurement of the Hall Effect in Trigonal Selenium Single Crystal

The Hall effect in trigonal selenium single crystals has been measured by a dc method. The measurements give a carrier concentration of 0.5×1015 cm−3 at room temperature and 1015 cm−3 at 100°K. The conductivity is of p type within the entire temperature range. By illumination with extrinsic light the carrier concentration has to a certain extent turned out to be independent of the intensity of light. The mobility calculated from a barrier model is about 260 cm2/V sec at room temperature in the direction of the c axis. The value is considerably higher than earlier reported values.