Polar dependent in-plane electric transport of epitaxial ZnO thin films on SrTiO(3) substrates.
Polar (001) and nonpolar (110) ZnO epitaxial thin films were grown on SrTiO(3) substrates by the pulsed laser deposition method and the in-plane electric transport was investigated. Both films display semiconducting behavior. The polar thin films have linear I-V relations with mobility increasing almost linearly with temperature. In contrast, for nonpolar ZnO thin films, the I-V curves are symmetric and nonlinear with room temperature resistivity 30 times larger than that of polar thin films. We conclude that in nonpolar ZnO thin films the bound polarization charge induced barrier limits the carrier transport. Instead, for polar thin films, the polar effect on the in-plane transport is negligible, and the charged dislocation scattering is dominant. Our observations suggest the polar effect should be considered in the design of ZnO related devices.
Laboratory of Advanced Materials, State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
Gaofeng
G
Sun
Kehan
K
Zhao
Yunlong
Y
Wu
Yuhang
Y
Wang
Na
N
Liu
Liuwan
L
Zhang