Improved thermal oxidation growth of non-flaking CuO nanorod arrays on Si substrate from Cu film and their nanoscale electrical properties for electronic devices

摘要

Single crystal cupric oxide (CuO) nanorod (NR) arrays are fabricated on Si substrates via a facile two-step strategy of sputter depositing Cu films followed by thermal oxidation. The Cu film with a structure of Si substrate/Cr or/and Cu fine grain buffer layer/Cu columnar crystal layer has been obtained by a step-by-step deposition process and employing different deposition parameters at each step. This structure is demonstrated to be beneficial for the NR growth and the NRs-substrate adhesion after thermal oxidation. The growth mechanism of the designed layer structure of Cu film and CuO NRs has been investigated. Both the fine grain buffer layer and Cu columnar crystal layer contribute to the diffusion of Cu atoms and the release of thermal stress during heating. To develop a Schottky nanocontact for electronic device, the nanoscale electrical properties of the p-type CuO NRs are characterized by conductive atomic force microscopy (C-AFM). The in-situ current-voltage (I-V) characterization shows that the upright standing CuO NRs exhibit good rectifying characteristics, which is attributed to the high specific surface area caused surface states. This study may promote the practical applications of p-type CuO nanostructures in electrical nanodevices.