Optical, Electrical Properties and Structure of Multilayer Iron-Doped Indium–Tin Oxide Thin Films Sputtered on Preheated Glass Substrates

抄録

Multilayer iron-doped indium-saving indium–tin oxide (ML ITO50:Fe₂O₃) thin films with high conductivity and high transmittance in the visible spectrum have been fabricated by sputtering method. Structures consisting of very thin layer of conventional indium tin oxide (90 mass% In₂O₃–10 mass% SnO₂) and iron-doped indium-saving indium–tin oxide layer with reduced content of In₂O₃ (ITO50:Fe₂O₃) to 50 mass% are discussed. By optimizing oxygen flow rate in iron-doped indium-saving indium–tin oxide layer, the lowest volume resistivity of 3.78 × 10⁻⁴ Ω·cm, mobility of 29.8 cm²/(V·s), carrier concentration of 4.60 × 10²⁰ cm⁻³ and transmittance larger than 90% in the visible range have been achieved. ML ITO50:Fe₂O₃ thin films deposited under optimal conditions demonstrated lower volume resistivity and higher transmittance than undoped multilayer indium-saving ITO thin films and iron-doped single-layer thin films obtained under the same oxygen flow rate Q(O₂) = 0.1 sccm. ML ITO50:Fe₂O₃ thin films demonstrated optimal parameters at the lower oxygen flow rate (Q(O₂) = 0.1 sccm) than undoped ML ITO50 thin films. ML ITO50:Fe₂O₃ thin films are crystallized and show In₄Sn₃O₁₂ structure.

Fig. 3 TEM images of as-deposited ML ITO50:Fe₂O₃ thin film: (a) plane view image from 2nd layer, (b) cross-sectional image and (c) plane view image closed to interface between 1st and 2nd layers. SAED patterns of 2nd layer (a) and closed to interface between 1st and 2nd layers (c).