Influence of incorporation of carbon on the transparent conducting properties of CdO thin films

Abstract

Thin films of CdO incorporated with different amounts of carbon element have been deposited on glass substrates by using the vacuum thermal evaporation method aiming at improving their transparent conducting (TC) properties. The structural and opto-electrical properties of the host CdO films were systematically studied. X-ray diffraction and optical investigations confirmed the inclusion of C species in the CdO lattice. The obtained results were explained through the occupation of interstitial positions and structural vacancies of the host CdO lattice by C species. It was observed that the inclusion of carbon into the CdO lattice blue-shifted the optical band gap by $${\sim }5{-}7$$ %, which was attributed to the Moss–Burstein (B–M) effect. The electrical studies showed that the carrier mobility increased steadily with the increase in the C% inclusion level, so that with 5 wt% it attained $${\sim }7.5$$ times the carrier mobility in un-doped CdO. Therefore, the present study showed that the prepared host CdO–C films have controllable TC degenerate semiconducting properties, which could be required in different optoelectronic applications.