Evaluation of different deposition conditions on thin films deposited by electrostatic spray deposition using a uniformity test

Copper indium disulphide films were produced by electrostatic spray deposition using a water/alcohol solution of copper chloride (CuCl2), indium chloride (InCl3) and thiourea (CS(NH2)2) sprayed onto SnO2:F coated glass substrates. The influence of various deposition parameters, namely substrate temperature (380-450 °C), applied voltage (12-18 kV), solution concentration (0.21-0.49 M), flow rate (25-200 μl/min) and needle-substrate distance (40-70 mm) were investigated. particle image velocimetry measurements were made of the spray cone and correlated with the film uniformity. The film uniformity was measured using an optically based test developed in-house. Results show that the highest concentrated spray solution and lowest deposition temperature produce non-uniform films. In contrast, a needle-substrate distance of 50 mm, and the lowest applied voltage and flow rate resulted in the most uniform films.