To measure the mechanical properties of Sb2S3, a two-component compound semiconductor used in the light absorption layer of a solar cell, Sb2S3 thin films were formed on FTO glass using the spin coating method. The spin-coated Sb2S3 thin films were heat-treated at 200 <sup>o</sup>C in an Ar atmosphere for up to 1 hour to form a thin film with continuous crystalline structures. A nanoindentation system was used to measure the mechanical properties of the spin-coated Sb2S3 thin films, and the phenomena appearing during indentation were analyzed. We used the continuous stiffness measurement (CSM) technique, and Young's modulus and hardness measured with the indentation depth of 250 nm were about 53.1 GPa and 1.43 GPa, respectively. The results were analyzed and compared with literature values, which varied from 40 GPa for the nanowire forms of Sb2S3 to 117 GPa, based upon simulation results. Since there are few studies on the mechanical properties of spin-coated Sb2S3 thin films, the results of this study are worthwhile. Besides, we observed that the Sb2S3 thin film had a little brittleness in the indentation test at higher load, and the microstructure was pushed around the indenter depending on the degree of bonding to the FTO glass substrate. This is a matter to be considered when making flexible devices in the future.
A Method to Extract the Intrinsic Mechanical Properties of Soft Metallic Thin Films Based on Nanoindentation Continuous Stiffness Measurement Technique
