p-type conductivity in CuCr[sub 1-x]Mg[sub x]O[sub 2] films and powders.

CuCr[sub 1-x]Mg[sub x]O[sub 2], a wide band gap semiconductor with the delafossite structure, has been synthesized in bulk and thin-film form. Bulk undoped CuCrO[sub 2] is almost 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 best p-type conductivity is 220 S cm[sup -1] in CuCr[sub 0.95]Mg[sub 0.05]O[sub 2], a factor of 7 higher than previously reported for Cu-based p-type delafossites. Undoped films have a conductivity of order 1 S cm[sup -1]. Films are usually polycrystalline on amorphous substrates, but undoped films can be c-axis oriented if deposited at or above 650 °C. Optical and ultraviolet transmission data indicate a direct band gap of 3.1 eV. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]