Growth and characterization of chromium selenide thin films for optoelectronic applications

Abstract

(TD) technique under a vacuum pressure of 10− 5 mbar. The films are structurally, morphologically, optically and dielectrically characterized. It is observed that CrSe2 thin films grown by TD technique exhibit optical excitations within direct and indirect allowed energy band gaps of 2.60 eV and 3.19 eV, respectively. The amorphous CrSe2 thin films contained a wide range of exponential band distribution presented by Urbach energy width of 2.24 eV. In addition in contrast to the chemical bath deposition technique which produced Cr7Se8 films of low dielectric constant ( r ∼ 2 ), the TD technique revealed high dielectric constant values up to r = 11.9 for CrSe2 films. Moreover, the Drude-Lorentz modeling of the imaginary part of the dielectric constant spectra revealed drift mobility values in the range of 0.70–6.45 cm2/ Vs. The plasmon frequency varied in the range of 5.42–8.33 GHz. Furthermore, analysis of the terahertz cutoff frequency ( fco ) spectra have shown that CrSe2 thin films exhibit fco values in the range of 3.30–40.0 THz. The features of CrSe2 thin films deposited by the thermal evaporation technique are promising semiconductor layers suitable for 6G and terahertz technology applications.