Fabrication and temperature-dependent band gap shrinkage of α-phase Bi2O3 thin films grown by atomic layer deposition method
Key Laboratory for Polar Materials and Devices of Ministry of Education, East China Normal University, Shanghai 200241, P.R. China
2 National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, P.R. China
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Accepted: 8 April 2013
Published online: 22 May 2013
α-Bi2O3 thin films were deposited on different substrates by atomic layer deposition method. The results of X-ray diffraction, high-resolution transmission electron microscopy and X-ray photoelectron spectroscope correspond to α-Bi2O3. The Fourier transform infrared spectroscopy analyses indicate that the reaction is rather complete during the deposition. Optical properties of the films have been investigated using ultraviolet-infrared transmittance spectra in the temperature range of 8–300 K. It is found that the band gap Eg decreases from 3.12 to 3.03 eV with the temperature. The parameters αB and ΘB of the Bose-Einstein model are 69.3 meV and 293.9 K, respectively. The band narrowing coefficient dEg/dT is −0.435 meV/K at room temperature. The present results can be considerable for future application of Bi2O3-based electro-optic and wide temperature range optoelectronic devices.
© EDP Sciences, 2013