Impact of selenization pressure on the micro-structural properties of Cu2ZnSnSe4 thin films

摘要: Abstract The Cu2ZnSnSe4(CZTSe) thin films were prepared by a two-step process consisting of high vacuum sequential evaporation precursors stack (Sn/Se/ZnSe/Se/Cu/Se) in 4-folds followed selenization at 350 °C tubular furnace under varied argon gas pressure from 1 mbar to 600 mbar with an interval 150 mbar. Cu/(Zn + Sn) and Zn/Sn ratios found vary 1.22 0.93 1.94 1.08 increase the stacks selenized for showed nearly stoichiometric composition slight Cu-poor Zn-rich values required CZTSe growth. X-ray diffraction studies revealed similar pattern preferred orientation along (112) plane, indicating formation kesterite-type all pressures. Raman spectra recorded using different excitation wavelength sources (785, 532 458 nm), two main peaks 192 172 cm−1 supplementary weak 82 232 cm−1 corresponding kesterite-ordered phase 600 mbar. Appreciable changes morphology have been noticed low dense irregular rod like compact spherical grain morphology. All samples absorption coefficient (>104cm−1). A variation optical band gap 0.90 1.01 eV was pressure. Hall effect measurements reveal that are p-type conductive. precursor exhibit mobility 7.88 cm2(Vs)−1 lower carrier concentration 2.54 × 1019 cm−3 resistivity order 10−2 Ωcm, respectively.