Abnormal current–voltage characteristics and metal–insulator transition of amorphous Fe-doped carbon films on Si substrates

• Published in: Physica. B, Condensed matter Vol. 403; no. 19; pp. 3434 - 3438
• Main Authors: Huang, Liubin, Hao, Lanzhong, Yan, Keyou, Xue, Qingzhong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2008; Elsevier
• Subjects: Amorphous semiconductors; glasses; Carbon films; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electrical properties; Electrical properties of specific thin films; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Metal–insulator transition; Physics; Raman spectrum; Electrical properties; 73.50.−h; 72.20.−I; Carbon films; Metal–insulator transition; 71.30.+h; Raman spectrum; Raman spectra; 73.50.-h; Metal-insulator transition; Amorphous state; Carbon; Cathode sputtering; Temperature effects; 72.20.-I; Iron additions; IV characteristic
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2008.05.004

Amorphous Fe 0.05–C 0.95 films have been deposited on n-type Si substrates using direct current magnetron sputtering. The structure and electrical properties of the films/Si are investigated. The film/Si deposited at room temperature exhibits abnormal current–voltage ( I– V) characteristics, whose current increases slowly at first, and then increases to a very large value when the voltage reaches a threshold. However, the I– V curves of the film on Si substrate deposited at 200 °C are almost linear. In addition, the temperature dependence of the resistance of the film/Si shows a metal–insulator transition and the transition temperature can be hugely modulated by increasing the external bias voltage. Finally, we propose a possible model to interpret the abnormal electrical properties of the film/Si.