Effect of precursor concentration and annealing temperature on the structural, optical and electrical properties of pure α-Fe2O3 thin films elaborated by the spin-coating method

We present a study of the influence of the precursor concentration and annealing temperature on structural, optical and electrical properties of the elaborated thin films of pure alpha-Fe2O3 deposited onto glass substrates using the spin-coating method. Three precursor concentrations (0.5 M, 0.6 M and 0.7 M) and three annealing temperatures (450, 500 and 550 degrees C) were used. X-ray diffraction shows that the films consist of pure polycrystalline with a trigonal structure and a strong preferential orientation for the plane (104). The crystallite size in pure alpha-Fe2O3 films was estimated using the Scherrer formula; it is found to vary between 17 and 43 nm for all films. Optical characterization, over a range of 290-1000 nm, reveals good optical transparency of about 80% in the visible region. The electrical resistively was measured by the four-point method. The results show that the resistivity is of the order of 10(-3) Omega cm for all concentrations or annealing temperatures used. Comparison between the obtained results shows that for the concentration 0.7 M and an annealing temperature between 500 and 550 degrees C, we have obtained the best crystallization of pure alpha-Fe2O3 thin films with high transparency and low resistivity.

Automated summary

This study investigates the influence of precursor concentration and annealing temperature on the properties of thin films made of pure alpha-Fe2O3. Results show that the best crystallization with high transparency and low resistivity is achieved with a precursor concentration of 0.7 M and annealing temperature between 500 and 550 degrees C.