Structure, optical and electrical properties of facing-target sputtered amorphous CNx films at low N2 partial pressures
Abstract
The structure, and the optical and electrical properties of CNx films, deposited by facing-target reactive sputtering at various N2 fractions (PN) in the gas mixture, have been studied systematically. XPS analyses indicate that N concentration increases with rising PN and reaches 28 at.% at a PN of 5%. The pure C films are mainly composed of sp3 C atoms. Increasing the N content in CNx films results in an increase of the number of sp2 C atoms and the size of aromatic sp2-hybridized C clusters, while the sp2 C remains relatively low content and rather small sized. Optical and electrical transport measurements show that all the films are semiconducting and the carrier transport is dominated by variable-range hopping between local electron states, due to the large number of defects in the films. With increasing PN, the optical band gap and room temperature resistivity increase due to the passivation of some defects in the tail states.
- Publication:
-
Journal of Physics D Applied Physics
- Pub Date:
- March 2007
- DOI:
- 10.1088/0022-3727/40/6/030
- Bibcode:
- 2007JPhD...40.1801W