GROWTH-MECHANISM AND ELECTRONIC-PROPERTIES OF DOPED PYRITE (FES2) CRYSTALS

FeS2 (pyrite) crystals of defined stoichiometry, high structural perfection and controlled dopant concentration were grown by chemical vapor transport. For Au-doping it has been found that the growth conditions at the surface of the crystal are changed leading to larger crystals of up to 8 mm edge length. An-doped crystals show n-type conductivity and a uniform Au-distribution of about 0.2 at% in the bulk. The carrier concentration varied from 6x10(15) to 9X10(17) cm(-3), the mobility ranged from 100-320 cm(2)/V.s (at room temperature). In comparison undoped crystals have about one order of magnitude lower carrier concentrations (7 X 10(14)-5 X 10(16) Cm-3). By using Co as doping agent carrier concentrations in the range 2 X 10(17)-3 X 10(19) cm(-3) were adjusted.