HIGH-PERFORMANCE CR₂O₃ THIN FILMS VIA OPTIMIZED SOL-GEL DEPOSITION: STRUCTURAL AND ELECTRICAL ANALYSIS

Abstract

Nanostructured Cr₂O₃ thin films were synthesized using the sol-gel method and deposited onto glass substrates by spin coating. The optimization of deposition parameters, including precursor concentration (0.5 M, 1.0 M, 1.5 M), spin speeds (1000, 2000, 3000 rpm), and deposition times (30, 60, 90 seconds), was performed using Design Expert software. The films were annealed at 500°C for 2 hours to promote crystallization. Characterization of the films was carried out using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The XRD patterns revealed a dominant (104) diffraction peak at 2θ = 36.5°, indicating the formation of Cr₂O₃ with a crystallite size of approximately 25 nm. FTIR spectra showed strong peaks at 570 cm⁻¹, confirming Cr-O bonding in the films. SEM images demonstrated smooth, uniform surfaces with no cracks at a spin speed of 2000 rpm, and AFM analysis revealed an average surface roughness of 3.2 nm. TEM images confirmed the nano-sized grains and homogeneity of the films. The electrical conductivity of the films was found to be 1.2 × 10⁻³ S/cm, and the thermal conductivity was measured at 0.85 W/m·K. The optimized Cr₂O₃ thin films exhibited good crystallinity, excellent morphology, and desirable electrical and thermal properties, making them suitable for applications in sensors and optoelectronics.