The Impact of Na and K on Properties of Cu2ZnSnS4 Thin Films Prepared by Ultrasonic Spray Technique

CZTS thin films are deposited onto glass and Mo-coated glass substrates by ultrasonic spray technique, followed by a sulfurization under argon atmosphere at 500 °C during 1 h. We have investigated how the addition of the alkali can influence Cu2ZnSnS4 thin films properties. X-ray diffraction and Raman spectroscopy proved that CZTS has the kesterite structure with a preferential orientation along 112. The values of Cu/(Zn+Sn) and (Zn/Sn) ratios, determined by energy dispersive spectroscopy, for undoped CZTS and alkali-doped CZTS are observed to be affected by the alkali doping. The electrical resistivity, for CZTS films deposited on glass substrates, decreased after alkali doping from 9.2 10−1 Ω · cm for undoped CZTS to reach 1.8 10−1 and 4.2 10−1 Ω · cm for 15% content of Na and K, respectively.