Exploring the relationship between reaction temperature and photodetection properties in Sb2Se3 thin film-based devices

This paper focuses on optimizing the reaction temperature of Sb2Se3 thin films for photodetector applications. The films were grown using a two-stage method on glass substrates. Structural analysis revealed the formation of the orthorhombic Sb2Se3 phase along the (020) plane, and increasing the reaction temperature up to 400 degrees C improved the crystal quality. Notably, the most promising structural properties were achieved for Sb2Se3 thin films reacted at 380 degrees C. Raman spectra confirmed the presence of tetragonal and amorphous selenium, along with Sb2Se3. Morphological analysis showed that a horizontally aligned rod morphology developed as the Sb2Se3 thin film grew, with the rod sizes increasing as the reaction temperature reached to 400 degrees C. X-ray photoelectron spectroscopy (XPS) revealed the formation of Sb-Se and Sb-O bonds, along with the presence of unreacted oxygen atoms near the surface of Sb2Se3 thin films reacted at 340 degrees C. Photoluminescence data indicated a bandgap value of 1.24 eV for Sb2Se3 films reacted at 380 degrees C. The current-voltage (I-V) curves exhibited a linear dependence for all Sb2Se3-based devices, suggesting ohmic contact between the films and the electrodes. The fastest photo- response was observed for the photodetector annealed at 380 degrees C, with rise and fall times of 26 ms and 40 ms, respectively. Additionally, the highest responsivity (R = 8.0 x 10-4 A/W), detectivity (D* = 3.8 x 106 Jones), and external quantum efficiency (EQE = 16.3%) were achieved by the same device, indicating that the optimal reaction temperature for Sb2Se3 thin films and their photodetector applications is approximately at 380 degrees C.