Effect of synthesis parameters on the structural, optical, morphological and electrical properties of n-type CTS nanostructures

In this work we have prepared n-type copper tin sulphide (CTS) quantum dot thin films for efficient window layers of solar cells. The change in type of CTS was achieved by the use of Triethanolamine (TEA) as the complexing agent. Studies were made on CTS thin films by changing the amount of complexing agent and also by changing the Cu:Sn and S:Sn ratios. All the samples showed low absorbance and high transmittance in the visible and infra red regions. The bandgaps are high enough to be used in buffer layers. Increasing the amount of TEA increased the crystallite size and thereby decreased the bandgap. Presence of excess copper in the material enhanced the conductivity of the material largely and also lead to the formation of Schottky barriers making Cu rich samples useful in rectification too. Increased sulphur content has been found to improve the crystallinity of CTS thin films.