Browsing by Author "Belkaid, M. S."

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The infuence of the mixed phase (Ti–TiO2(A): TiO2(R)) on the optical band gap of TiO2 nanotubes heat treated at diferent temperatures
(Springer Nature link, 2023) Zalouk, Djedjiga; Hatem, D.; Hocine, D.; Belkaid, M. S.; Hadjersi, T.; Kebbati, Y.; Boudinar, S.
Highly ordered TiO2 nanotubes (NTs) were synthesized by electrochemical anodization than annealed at diferent temperatures between 300 and 900 °C for 3 h. The elaborated NTs adhere well to the Ti substrate over the annealing temperature range of 300–600 °C. The TiO2 NTs morphology begins to gradually evolve for temperatures up to 700 °C and approaches that of nanoparticles until the latter become predominant at T above 800 °C. Refection measurements show that the NTs present refection of 7% at 600 °C, corresponding to the lowest band gap 2.59 eV. This can be related to the presence of the mixed phase (Ti–TiO2(A)–TiO2(R)).The charge carrier density decreases from 2.34× 10+21 to 3.61× 10+13 cm−3when the annealing temperature increases, that accompanied by a reduction in the resistivity from 142.23 to 29.56Ω.cm which is adequate to photo anode application.
Measurement of Square Resistance In Situ of SnO2: F Thin Film With Annealing at High Temperature Under Air
(ICTP, 2008) Tahi, Hakim; Boumaour, Messaoud; Tala-Ighil, Razika; Belkaid, M. S.
Thin films of fluorine doped tin oxide (SnO2: F), deposited by spray pyrolysis on silicon substrate, were characterized by the method of four points probe in situ during annealing at high temperature under air. The evolution of square resistance (in situ) with the annealing temperature was interpreted in terms of competition between electronic conduction and ionic conduction. A square resistance of 136�/□ is measured before annealing and after annealing at 900°C, the square resistance increases appreciably to reach 40k�/□. This increase is explained by the absorption of oxygen at the films surface and an increase in SiO2 thickness at interface SnO2/Si