p-type conductivity in CuCr{sub 1{minus}x}Mg{sub x}O{sub 2} films and powders

CuCr{sub 1{minus}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 Scm{sup {minus}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 Scm{sup {minus}1}. Films are usually polycrystalline on amorphous substrates, but undoped films can be c-axis oriented if deposited at or above 650{degree}C. Optical and ultraviolet transmission data indicate a direct bandgap of 3.1 eV. {copyright} 2001 American Institute of Physics.