EFFECT OF THE DEFECT STATES DENSITY ON OPTICAL BAND GAP OF CdIn2O4 THIN FILM
来源期刊：Acta Metallurgica Sinica2005年第3期
论文作者：B. Li Z.G. Wu H.S. San B.X. Feng
Key words：sputtering; CdIn2O4 thin film; electrical property; optical property;
Abstract: Transparent conducting oxides CdIn2O4 thin films were prepared by radio-frequency reactive sputtering from a Cd-In alloy target in Ar+O2 atmosphere. By transmission spectrum and Hall measurement for different samples prepared at different substrate temperatures, it could be found that the carrier concentration would increase with the decrease of substrate temperature, but absorption edge showed an abrupt variation from a blue shift to a red shift.Theoretically, the paper formulated the effect of high-density point defects on band structures; it embodied the formation of band tailing, Burstein-Moss shift and band-gap narrowing. The density of holes will influence the magnitude of optical band gap and transmittance of light. Since extrapolation method does not fit degenerate semiconductor materials, a more accurate method of obtaining optical band gap is curve fitting. In addition, ionized impurities scattering is the main damping mechanism of the free electrons in CdIn2O4 films, the density of ionized impurities induced by altering substrate temperature will affect the carriers mobility.
B. Li1，Z.G. Wu2，H.S. San2，B.X. Feng2
(1.Shanghai Institute of Technical Physics, The Chinese Academy of Sciences, Shanghai 200083, China;
2.Key Laboratory for Magnetism and Magnetic Material of Ministry of Education, Lanzhou University,Lanzhou 730000, China)
Abstract:Transparent conducting oxides CdIn2O4 thin films were prepared by radio-frequency reactive sputtering from a Cd-In alloy target in Ar+O2 atmosphere. By transmission spectrum and Hall measurement for different samples prepared at different substrate temperatures, it could be found that the carrier concentration would increase with the decrease of substrate temperature, but absorption edge showed an abrupt variation from a blue shift to a red shift.Theoretically, the paper formulated the effect of high-density point defects on band structures; it embodied the formation of band tailing, Burstein-Moss shift and band-gap narrowing. The density of holes will influence the magnitude of optical band gap and transmittance of light. Since extrapolation method does not fit degenerate semiconductor materials, a more accurate method of obtaining optical band gap is curve fitting. In addition, ionized impurities scattering is the main damping mechanism of the free electrons in CdIn2O4 films, the density of ionized impurities induced by altering substrate temperature will affect the carriers mobility.
Key words:sputtering; CdIn2O4 thin film; electrical property; optical property;
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