Hall effect measurement in semiconducting chalcogenide glasses and liquids

A Hall effect measurement technique is described which overcomes some of the difficulties presented by materials combining a small Hall angle with a large temperature coefficient of conductivity. The major problem of `offset' voltage suppression is dealt with by using a direct primary current in conjunction with an alternating magnetic field and narrow-bandwidth phase-conscious signal detection. The method has been used to study the temperature dependence of the Hall mobility in some chalcogenide glasses and liquids in the systems As-Se-Te and As-Se-Te-Tl between 20 and 500°c. The mobilities are generally about 10-1 cm2 v-1 sec-1 and show only weak temperature dependence. The Hall coefficients are always negative for the amorphous materials while the thermoelectric powers are always positive. The implications of these results are briefly discussed.