Substrate temperature effect on the crystal growth and optoelectronic properties of sprayed α-Fe₂O₃ thin films: application to gas sensor and novel photovoltaic solar cell structure

ABSTRACT

 Iron oxide (Fe₂O₃) thin films were deposited on glass substrate by varying substrate temperature (T_s) from 300 to 450°C using spray pyrolysis technique. The effect of T_s on the physical properties of Fe₂O₃ layers was studied. The XRD spectra reveal the formation of α-Fe₂O₃. The best crystallinity is obtained at T_s = 400°C. Optical analysis allows us to know that α–Fe₂O₃ thin films displayed a band gap from 2.07 to 2.16 eV for direct transition and from 1.67 to 2 eV for indirect transition. The maximum value of Hall mobility (µ = 62cm².V⁻¹. s⁻¹) is obtained at T_s = 400°C. Hence, the obtained result of gas sensing proves that α-Fe₂O₃ has good sensitivity and stability at operating temperature equal to 300°C. Besides, CuO/α-Fe₂O₃/ZnO has a photovoltaic effect. That the open circuit voltage (V_oc) and short circuit current density (J_sc) are equal to 0.5 V and 0.43 mA/cm² respectively.

KEYWORDS:

• Spray pyrolysis
• α-Fe₂O₃ thin film
• physical properties
• gas sensor
• solar cell

Disclosure statement

No potential conflict of interest was reported by the authors.