Optical properties and electrical resistivity of boron-doped ZnO thin films grown by sol–gel dip-coating method

Abstract

Sol–gel dip-coating was used to grow ZnO thin films doped with various concentrations of B ranging from 0 to 2.5at.% on quartz substrates. The effects of B doping on the absorption coefficient (α), optical band gap (Eg), Urbach energy (EU), refractive index (n), refractive index at infinite wavelength (n∞), extinction coefficient (k), single-oscillator energy (Eo), dispersion energy (Ed), average oscillator strength (So), average oscillator wavelength (λo), moments M−1 and M−3, dielectric constant (ε), optical conductivity (σ), and electrical resistivity (ρ) of the BZO thin films were investigated. The transmittance spectra of the ZnO and BZO thin films show that the transmittance of the BZO thin films was significantly higher than that of the ZnO thin films in the visible region of the spectrum and that the absorption edge of the BZO thin films was blue-shifted. The BZO thin films exhibited higher Eg, EU, and Eo and lower Ed, λo, M−1 and M−3 moments, So, n∞, and ρ than the ZnO thin films.