Effect of annealing on the structural, optical and electrical properties of (F, Zn) double doped SnO2 nanoparticles obtained by the laser pyrolysis method

• Published in: Materials science in semiconductor processing 2022-05, Vol.142, p.106511, Article 106511
• Main Authors: Morjan, Iuliana P., Dutu, Elena, Fleaca, Claudiu T., Dumitrache, Florian, Morjan, Ion, Mihailescu, Natalia, Demian, Mihai, Teodorescu, Valentin S., Scarisoreanu, Monica
• Format: Article
• Language: English
• Subjects: Annealing effect; Double doped tin oxide; Laser pyrolysis technique; Tuning photoluminescence properties
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2022.106511

SnO2 nanoparticles have a great potential in photocatalytic and optoelectronic applications by extending their absorbtion and emission from UV to the visible domain. The effect of annealing at 750 °C and 1000 °C for 3 h in ambient conditions on structural, optical and electrical properties of F&Zn double doped SnO2 nanoparticles synthesized by continuous wave CO2 laser pyrolysis method were investigated for the first time. X-Ray diffraction studies confirmed the expected crystallite size increasing and also the vanishing of divalent tin phases (SnF2, SnO) upon air annealing. Detailed X ray photoelectron spectroscopy (XPS) analysis confirmed that fluorine disappears completely from SnO2 structure at 1000 °C. The annealing also induced a reduction in oxygen vacancies as confirmed by Raman spectroscopy and XPS. Transmission FTIR spectroscopy was used for revealing the existence of Sn–O, O–Sn–O, O–H and H–O–H vibrational modes. The optical band gap energies of all annealed samples are in the visible region, decreasing for those that were initially doped with F, and increasing for the only Zn doped sample. Photoluminescence (PL) measurements showed a broad dominant peak in green visible region, around 530 nm. For the sample with the highest content of Zn, PL spectrum shifted to higher wavelengths, respectively to the orange and red regions. The oxygen vacancies concentrations after annealing are correlated with the electrical conductivity of F, F&Zn, and Zn doped SnO2 samples. [Display omitted] •F&Zn double doped SnO2 nanoparticles obtained by laser pyrolysis method were air annealed at 750 °C (and at 1000 °C).•The oxygen vacancy concentration along the rutile lattice c-axis decreases due to the decrease of the F content and increase in the direction perpendicular on the c-axis, because of the increase of the Zn content.•F doped and Zn/F co-doped SnO2 nanoparticles generally showed a decrease in BG (bandgap) after 750 °C annealing, except for the only Zn doped sample.•PL spectrum shifted to red region for the highest Zn content SnO2 nanoparticles.•The air annealing temperature influences both oxygen vacancy concentration and electric conductivity of all doped samples.