p-type conductivity in CuCr1-xMgxO2 films and powders

CuCr1-xMgxO2, a wide band gap semiconductor with the delafossite structure, has been synthesized in bulk and thin-film form. Bulk undoped CuCrO2 is al most black and has moderate conductivity with p-type carriers. Upon doping with 5% Mg, the conductivity increases by a factor of 1000. In films, the b est p-type conductivity is 220 S cm(-1) in CuCr0.95Mg0.05O2, a factor of 7 higher than previously reported for Cu-based p-type delafossites. Undoped f ilms have a conductivity of order 1 S cm(-1). Films are usually polycrystal line on amorphous substrates, but undoped films can be c-axis oriented if d eposited at or above 650 degreesC. Optical and ultraviolet transmission dat a indicate a direct band gap of 3.1 eV. (C) 2001 American Institute of Phys ics.