Investigating the Suitability of Cu₂ZnSnS₄ Thin Films for Gamma Radiation Dosimetry Applications in Nonmedical Environments

The need for the replacement of cadmium, indium, and tellurium in their compounds for sensor applications is a novel study. The copper zinc tin sulfide (Cu₂ZnSnS₄) thin films were synthesized from Cu (99.99%), Sn (99.99%), and Zn (99.99%) using the thermal evaporation method. The same volumetric parameters were maintained throughout the synthesis process. The films were further irradiated using an isotope of cesium-137 (Cs-137) from a gamma source at different doses (0–0.6 kGy) and dose rates of 0.1007 Gy/h at room temperature. Both the pristine (0 kGy) and irradiated (0.1, 0.3, and 0.6 kGy) films were characterized with a Raman spectroscope, a field emission scanning electron microscope (FESEM) with the JEOL JSM-7600F model, energy dispersive X-rays (EDX), an ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscope, and four-point probe techniques. The Raman results confirmed that all the films for both pristine and irradiated films have a main and secondary phases. The EDX results showed that the pristine and 0.1 kGy films were Cu-rich films, while the 0.3 kGy and 0.6 kGy films turned out to be Zn-rich films with an increase in gamma radiation dose. The optical properties of all the films showed also that the band gap decreased from 1.6 to 1.48±0.03 eV for the pristine and irradiated films, while the electrical resistivity results decreased as the gamma radiation dose increased. However, as the structural, optical, and electrical properties of the Cu₂ZnSnS₄ thin films responded linearly with the increasing gamma radiation dose, this suggests the usefulness and possibility of designing a new solid-state sensor for dosimetry applications to replace cadmium telluride (CdTe) and copper indium gallium sulfide (CIGS) thin films.