Low dimensional (0D and 1D) nanoscale semiconducting metal oxide materials have attracted much attention because they have new functional properties and numerous applications [Zirak M. 2014, Comini E. 2013, and Kulyk B. 2010]. Since one-dimensional (1D) cadmium oxide (CdO) such as nanowires (NWs), as an important n-type semiconductor metal oxide, has also widely investigated owing to its potential applications in optical fields, photovoltaic cells and transparent electrodes [Kaviyarasu K. 2014, Yousef A. 2012,and Kamblea A.S. 2011].
The aim of the present work is study the crystal structure, the chemical composition, photoluminescence and the optical constants of CdO nanowires.
The experimental setup for the vapor transport growth of CdO NWs consisted of a horizontal tube furnace with an alumina tube and equipped with gas supply.
The synthesis temperature was chosen via thermal gravimetry analysis (TGA) and it was 1150oC. The formation of CdO was confirmed by energy dispersive analysis of X-ray (EDAX) and Fourier transform infrared (FT-IR) spectroscopy analysis. The CdO nanowires was found to grow via a vapor–solid growth mechanism. The diameters of the nanowires were in the range 30–90 nm and the lengths were greater than 30 μm. The optical constants, the thickness and the surface roughness of the prepared CdO NWs films were determined by spectroscopic ellipsometry measurements. A two layers model was used to fit the calculated data to the experimental ellipsometric spectra. The obtained optical constants were compared with those obtained by other preparation methods. The optical band gap was found to be 2.41 eV. An emission peak at ≈550 nm was recorded, which should corresponds to the near band-edge emission of CdO.
With such a strong emission peak at ~550 nm, the CdO NWs can be utilized in the industry of high quality monochromatic laser.
Thus, the above described properties may find profound applications in optoelectronic devices such as light-emitting devices and high quality monochromatic laser.