1989 Volume 30 Issue 11 Pages 908-914
The electrical conductivity of a scandium sulfide disk prepared by a new synthesizing method which is carefully developed to avoid contamination has been measured at temperatures ranging from 773 to 1223 K and at sulfur partial pressures ranging from 10−7 to 104 Pa. It has been found that scandium sulfide is an n-type semiconductor and the sulfur pressure dependence of the conductivity in the temperature range higher than 993 K differs from that of in the temperature range lower than 993 K. The specific conductivity (S/m) is expressed as follows:
in the high temperature range (1023∼1223 K)
σn=7.94×105PS2−3⁄16exp(−1.14×105⁄RT),
and in the low temperature range (773∼973 K)
σn=1.44×107PS2−1⁄4exp(−1.38×105⁄RT),
where P is expressed in Pa and R in J/mol.
The observed sulfur pressure dependence is attributed to fully ionized scandium interstitials in the high temperature range and to either monovalent sulfur vacancies or divalent sulfur vacancies owing to the dissolution of divalent impurities in the low temperature range.
