Experimental investigation of pure spinel Mn3O4 properties synthesized through chemical spray pyrolysis for future gas sensor application

The semiconductor’s realization is a very significant stage in gas sensor application. Herein, the Mn3O4 semiconductors were deposited using chemical spray pyrolysis. The effect of deposition temperature on structural, vibrational optical and electrical Mn3O4 thin layers properties were investigated through: X-ray diffraction, Raman spectroscopy, UV-visible spectrophotometer, and two points electrometers respectively. The X-ray diffraction showed the appearance of spinel phase of tetragonal Mn3O4 with strong formation direction along (101) plan and without any secondary phase indicating the formation of pure Mn3O4. The Raman spectroscopy confirmed the results obtained in XRD and certified the high-quality formation of Mn3O4. In addition, the crystallinity improvement (the increase of crystallite size and the decrease of dislocation density) was caused by the increasing of deposition temperature from 350°C to 450°C. Optical properties such as transmittance, absorbance and band gap energy were extracted by UV-Visible spectrophotometer. Thus, low transmittance, high absorbance and small band gap energy were observed at the highest substrate temperature (450°C). The electrical conductivity showed good values between 4.83 and 13.89 mS.cm-1. These properties make Mn3O4 an appropriate material to be used as a sensitive layer in gas sensors applications.