Energy band engineering and controlled p-type conductivity of CuAlO2 thin films by nonisovalent Cu-O alloying

The electronic band structure and p-type conductivity of CuAlO2 films were modified via synergistic effects of energy band offset and partial substitution of less-dispersive Cu+ 3d(10) with Cu2+ 3d(9) orbitals in the valence band maximum by alloying nonisovalent Cu-O with CuAlO2 host. The Cu-O/CuAlO2 alloying films show excellent electronic properties with tunable wide direct bandgaps (similar to 3.46-3.87 eV); Hall measurements verify the highest hole mobilities (similar to 11.3-39.5 cm(2)/Vs) achieved thus far for CuAlO2 thin films and crystals. Top-gate thin film transistors constructed on p-CuAlO2 films were presented, and the devices showed pronounced performance with I-on/I-off of similar to 8.0 x 10(2) and field effect mobility of 0.97 cm(2)/Vs. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3683499]