Structural, optical and electrical characterization of epitaxial Cr2O3thin film deposited by PLD

Thin film of chromium oxide (Cr 2 O 3 ) having thickness ∼400 nm, was deposited on sapphire substrate by using pulsed laser deposition (PLD) technique. Structural, morphological and optical properties of prepared thin film were investigated using x-ray diffraction (XRD), atomic force microscopy (AFM) and UV–vis spectrophotometry. XRD result confirmed the epitaxial growth of Cr 2 O 3 thin film with preferred orientation along (006) plane and crystallizes in rhombohedral structure as well. AFM analysis showed a very smooth film with root mean square roughness of 0.1 nm. Electrical resistivity measurements were carried out using two-probe method and found resistivity of 11.52 kΩ-cm. The average transmittance recorded from optical transmission spectra is 70% within the wavelength range of 200–800 nm. The dispersion of refractive index was investigated by the Wemple-Di Domenico single oscillator model. The oscillator parameters i.e. single-oscillator energy E o , the dispersion energy E d , zero-frequency dielectric constant ( ε ), and optical conductivity have also been determined. Extinction coefficient, dielectric constant, Urbach and band gap energy were also calculated. This work can further lead to the development of highly effective p-type transparent conducting oxide material for optoelectronic applications.