N. E. Hakiki
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ABSTRACT: The structural and photoelectrochemical characterization of thermally grown oxide films on stainless steel is performed by
near field microscopy and photocurrent measurements. The results show that the film formed at highest temperature has a very
small grain size with a small surface roughness. A decrease of the grain size with increasing temperature is obtained. The
images obtained on oxide formed at low temperature show that the film compactness decreases with temperature especially at
50°C where the film is partially formed. The results obtained by photocurrent measurements show an increase of the quantum
efficiency with temperature. A band gap energy value around 2.3eV is obtained whatever the nature of the film obtained. Plots
of the quantum efficiency as a function of the energy incident light reveal the existence of a photocurrent peak located in
the band gap region, at 1.9eV, near the conduction band. The analysis of the photocurrent as a function of the applied potential
reveals a Pool–Frenkel effect. The donor densities extracted from photoelectrochemical measurements are compared to those
obtained in previous works by capacitance measurements. The investigation shows that the electronic structure of oxide films
formed on stainless steel can be described on the basis of the band structure model developed for crystalline semiconductor
materials.
Journal of Applied Electrochemistry 04/2012; 40(2):357-364. · 1.75 Impact Factor
