Experimental Investigation of Pure Spinel Mn₃O₄ Properties Synthesized through Chemical Spray Pyrolysis for Future Gas Sensor Application

Abstract

Abstract The semiconductor realization is a very significant stage in gas sensor application. Herein, the Mn 3 O 4 semiconductor was deposited using chemical spray pyrolysis. The effect of deposition temperature on structural, vibrational optical and electrical Mn 3 O 4 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 Mn 3 O 4 with strong formation direction along (101) plan and without any secondary phase indicating the formation of pure Mn 3 O 4 . The Raman spectroscopy confirmed the results obtained in XRD and certified the high‐quality formation of Mn 3 O 4 . 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 Mn 3 O 4 an appropriate material to be used as a sensitive layer in gas sensors applications.