Appearance of n-type semiconducting properties of cBN single crystals grown at high pressure

Semiconducting properties of two types of cubic boron nitride (cBN) single crystals prepared at high pressure and high temperature were evaluated by Hall measurement. Sulfur was intentionally doped in one type as a donor and the other type contained no intentional dopants. Both crystals exhibit n-type conduction. Sulfur-doped and nonintentionally doped crystals show donor levels and carrier concentrations of 0.32 eV and 10(14)cm(-3), and 0.47 eV and 10(12)cm(-3) at room temperature, respectively. The origin of n-type conduction of nonintentionally doped crystal has not been elucidated but oxygen appears to be a candidate for the donor in the crystal.