Roughness-based monitoring of transparency and conductivity in boron-doped ZnO thin films prepared by spray pyrolysis

Sprayed polycrystalline ZnO and boron-doped ZnO thin films composed of spherical grains of 25–32 nm in diameters are used in roughness measurement and further correlated with the transparency and the conductivity characteristics. The surface roughness is increased up to Zn0.98B0.02O and then declined at higher boron concentrations. The sprayed ZnO films revealed ≥95% transmittance in the visible wavelength range, 1.956 × 10−4 Ω cm electrical resistivity, 46 cm2/V s Hall mobility and 9.21 × 1021 cm−3 charge carrier concentration. The X-ray photoelectron spectroscopy study has confirmed 0.15 eV binding energy change for Zn 2p3/2 when 2 at% boron content is mixed without altering electro-optical properties substantially. Finally, using soft modeling importance of these textured ZnO over non-textured films for enhancing the solar cells performance is explored.

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► We report surface roughness dependent transparency and conductivity in ZnO films.
► The surface roughness with respected to boron doping concentrations is studied.
► Boron doped and pristine Zinc oxide thin films have showed ≥95% transmittance.
► Increased carrier concentration of 9.21 × 1021 cm−3 revealed from Hall measurement.