Sol-Gel-Derived High-Performance Stacked Transparent Conductive Oxide Thin Films

Single- and multi-layer transparent conductive oxide (TCO) thin films exhibiting high performance, good packing density and low surface/interface roughness are deposited on silica glass substrates by the sol-gel method. The crystal and microstructural properties of the TCO thin films are evaluated as an alternate to films prepared by ultra-high vacuum deposition. Tin-doped indium oxide (ITO) thin films produced using a two-step drying process showed low surface roughness because of dense packing structure not only horizontal but also vertical directions. As a result, electrical conductivity, carrier concentration, carrier mobility, and optical transmittance of 2.3 x 10(3)S/cm, 8x10(20)cm(-3), 18cm(2)/Vs, and over 98% at 500nm, respectively, were achieved. A multilayer ZnO/ITO stacked structure was also fabricated using the sol-gel process. Our findings suggest that solution-based methods show promise as an alternative to existing ultra-high vacuum methods to fabricate TCO thin films.