Preparation, characterization and electrical transport properties of individual α-MnO2 and β-MnO2 nanorods

Electrical transport experiments are performed on individual α-MnO2 and β-MnO2 nanorods. Both of α-MnO2 and β-MnO2 nanorods are synthesized via hydrothermal routes. A three-region method is used to analyze their nonlinear current–voltage characteristics. Under low biases, the effective contact barrier height is roughly estimated to be 0.05 eV for α-MnO2 and 0.15 eV for β-MnO2, respectively. As the applied bias is high enough, the contact barriers are significantly tilted and the current is largely tunneling. The conductance of α-MnO2 and β-MnO2 nanorods at room temperature is roughly estimated to be 5.98 and 1.74 × 10−3 cm−1 Ω−1, respectively. And the thermal-activation energy is roughly estimated to be 0.047 and 0.226 eV, respectively. Our results are probably the bases for their applications in nanosized electrical devices.