We report variable temperature resistivity measurements and mechanisms related to electrical conduction in 200 keV Ni 2+ ion implanted ZnO thin films deposited by vapor phase transport. The dc electrical resistivity versus temperature curves show that all polycrystalline ZnO films are semiconducting in nature. In the room temperature range they exhibit band conduction and conduction due to thermionic emission of electrons from grain boundaries present in the polycrystalline films. In the low temperature range, nearest neighbor hopping (NNH) and variable range hopping (VRH) conduction are observed. The detailed conduction mechanism of these films and the effects of grain boundary (GB) barriers on the electrical conduction process are discussed. An attempt is made to correlate electrical conduction behavior and previously observed room temperature ferromagnetism of these films.
|Number of pages
|Applied Physics A: Materials Science and Processing
|Published - May 2012
Bibliographical noteFunding Information:
We are thankful to Dr. Neeraj Khare, IIT Delhi for various important discussions. One of the authors (B. Joshi) gratefully acknowledges the financial support from Department of Science and Technology (DST) and University Grants Commission (UGC), New Delhi.