Stress-induced phase-alteration in solution processed indium selenide thin films during annealing

This article demonstrates the successful synthesis of indium selenide thin films by a spin coating method in air using thiol-amine cosolvents. The synthesized films encountered a transformation from beta-In3Se2 to gamma-In2Se3 phase due to mechanical stress during annealing as confirmed from XRD and EDS analysis. The SEM study ensured the homogeneity and uniformity of surface morphology of both phases. The FTIR analysis also confirmed the In-Se stretching vibration bond for both beta-In3Se2 and gamma-In2Se3 thin films. The temperature dependent electrical conductivity indicated the semiconducting nature of both phases. The optical transmittance was found to increase with annealing temperatures for both phases. The optical band gaps were estimated to be in the range of 2.60-2.75 and 2.12-2.28 eV for beta-In3Se2 and gamma-In2Se3 phases, respectively consistent with the reported values. These results indicate that stress-induced phase transformation in solution-processed indium selenide could be useful in 2D optoelectronic devices in future.

Automated summary

This study successfully synthesized indium selenide thin films using a spin coating method in air, demonstrating a phase transformation from beta-In3Se2 to gamma-In2Se3 due to mechanical stress during annealing. Analysis using various techniques confirmed the properties and structure of both phases. Electrical conductivity and optical transmittance tests supported the potential application of stress-induced phase transformation in solution-processed indium selenide for future 2D optoelectronic devices.