Low-Temperature Nanocluster Deposition (NCD) for Improvement of the Structural, Electrical, and Optical Properties of ITO Thin Films

Indium tin oxide (ITO) thin films were grown using nanocluster deposition (NCD) on glass substrates in low temperature range from 170 to 250°C. X-ray diffraction pattern revealed that ITO thin films deposited above 200°C were preferentially oriented along (1 1 1) direction. A dramatic change in electrical properties of ITO thin films deposited from 200 to 170°C was attributed to the change in microstructure and chemical bonding states. The ITO thin films deposited at 170°C exhibited semiconducting properties with high optical transmittance of 95% at 550-nm wavelength. Films of approximately 140 ± 5 nm thicknesses exhibited both the lowest resistivity of 7 × 10^-4 Ω·cm and the figure-of-merit value of 1.3 × 10^-2 Ω^-1. The NCD technique is possible for deposition of ITO films crystallized at low temperatures below 200°C on glass or flexible polymer substrates.