(Color online) The XRD patterns of the Sn0.95TM0.05O2 (TM: Mn or Fe) films with different oxygen pressure. The diffraction peak at about 18.4° in the Sn0.95Mn0.05O2 films with the oxygen pressure of 10−2 and 10−1 Pa, ascribed to the tetragonal phase of SnO, is remarked by label (*). The inset shows the variation of the a-axis lattice constants evaluated from the diffraction peak (110) as the oxygen pressure.
(a) and (b) Surface and (c) and (d) cross-sectional SEM images of the Mn and Fe doped SnO2 films grown under oxygen pressure of 10−1 Pa, respectively. Note that the given scales in the pictures (b) and (d) are 1 μm and 500 nm, respectively.
(Color online) XPS spectra of the (a) Sn 3d, (b) Mn 2p, and (c) Fe 2p regions for the Sn0.95TM0.05O2 films prepared with oxygen pressure of 10−1 Pa. (d), (e), and (f) Oxygen pressure dependence of the corresponding binding energy positions.
(Color online) O 1s reference spectra of the Sn0.95Mn0.05O2 (left) and Sn0.95Fe0.05O2 (right) films as a function of oxygen pressure, respectively.
(Color online) (a) Experimental infrared reflectance spectrum (dotted line) and the best-fit result (solid line) of the Sn0.95Mn0.05O2 film grown under 10−1 Pa. The phonon modes can be clearly assigned by the dashed lines. (b) and (c) An enlarged frequency region of 550–650 cm−1 from the experimental reflectance spectra for the Sn0.95TM0.05O2 (TM: Mn or Fe) films. (d) and (e) The doping effects on the optical functions of the Sn0.95TM0.05O2 films deposited under the oxygen pressure of 10−1 Pa. The horizontal coordinate is the logarithmic unit to emphasize the lattice vibration region. (f) The corresponding variations with the oxygen pressure for the highest frequency E u (TO) phonon modes.
(Color online) Experimental (dotted lines) and best-fit (solid lines) transmittance spectra taken from the Sn0.95TM0.05O2 (TM: Mn or Fe) films with the oxygen pressure of 10−1 Pa. For clarity, the insets exhibit all experimental transmittance spectra of the films deposited under different oxygen pressure from ultraviolet to near-infrared photon energy region.
(Color online) The left panel shows the refractive index n and the extinction coefficient κ for the Sn0.95TM0.05O2 (TM: Mn or Fe) films grown under the oxygen pressure of 10−1 Pa. The right panel shows the variation trends of the electronic transition energies from the Tauc-Lorentz’s parameters with the oxygen pressure.
(Color online) A three peak fitting of the photoluminescence spectra for the Sn0.95TM0.05O2 (TM: Mn or Fe) films grown under different oxygen pressure. Note that some spectral lineshapes are enlarged by several times for a comparison.
(Color online) The oxygen pressure dependence of photoluminescence intensities and peak positions for the Sn0.95TM0.05O2 (TM: Mn or Fe) films. It indicates that there are different variation trends for Mn or Fe doped SnO2 materials with the oxygen pressure.
Comparison of binding energies from Sn 3d, O 1s, and TM 2p for various oxygen pressures in the Sn0.95TM0.05O2 (TM: Mn or Fe) films and the peak positions of photoluminescence spectra are determined from the Gaussian fitting.
The Lorentz multi-oscillator parameter values for the Sn0.95TM0.05O2 (TM: Mn or Fe) films with the varied oxygen pressure are extracted from the best fitting to infrared reflectance spectra in Fig. 5 .
The Tauc-Lorentz’s parameter values for the Sn0.95TM0.05O2 (TM: Mn or Fe) films are determined from the simulation to ultraviolet-near-infrared transmittance spectra in Fig. 6 .
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