Spray solution flow rate effect on growth, optoelectronic characteristics and photoluminescence of SnO2:F thin films for photovoltaic application

This paper deals with the study of photoluminescence (PL) and the other physical properties (structural and optoelectronic) of fluorine doped tin oxide (SnO2: F) thin films with controlled disorder and intrinsic defects induced during elaboration by changing the spray solution flow rate from 10 to 25 mL min−1 by a step of 5 mL min−11. X-Ray Diffraction analysis reveals that SnO2:F thin films have a tetragonal structure with (2 0 0 0) preferred orientation. The decrease in the PL intensity peaks with increase in the spray solution flow rate is linked with the decrease in intrinsic defects. The infrared transmission cut-off wavelength of the films shifts towards the lower wavelength with increasing the spray solution flow rate. This result corresponds to an increase of the electron concentration. In fact, the infrared reflectance of the layers shows an increase with increasing electron concentration. All the samples have low transmittance and high reflectance in the near-infrared region. But in the visible, the average transmittance of these films is higher than 85%. The minimum resistivity (1.76 × 10−4 Ω cm) and maximum Hall mobility (μ = 47 cm2 V−1 s−1) were obtained at spray solution flow rate equals to 25 mL min−1. This good optoelectronic quality of this material allows us to use it as an ohmic contact in photovoltaic devices such as CuIn1−yGayS2/β-In2−zAlzS3/ZnO. This solar cell has a photovoltaic effect. Thus, the open circuit voltage (Voc) and short circuit current density (Jsc) are equal to 340 mV and 1.25 mA cm−2, respectively.