title: Investigation of the dielectric function of solution-processed InGaZnO films using ellipsometry.
abstract: The optical properties of InGaZnO (IGZO) films grown through the sol-gel process as a function of sintering time were investigated with spectroscopic ellipsometry (SE). The IGZO precursor sol was prepared by mixing In nitrate, Ga nitrate, and Zn acetate at a molar ratio of In:Ga:Zn = 3:1:1. The solution was deposited on a SiO2/Si substrate via spin coating. Sintering was performed at 400 degrees C for 1-15 h in an ambient atmosphere. The optical properties were measured over the range 1.12-6.52 eV via variable angle SE, at room temperature. The angle of incidence was varied from 50 to 70 degrees in 5 degree steps. To extract the pure optical properties of IGZO, multilayer-structure calculation with Tauc-Lorentz dispersion relation for IGZO was performed. The changes in the dielectric function of the IGZO films with varying sintering time were observed. The resultant optical properties can be related to the concentration of oxygen vacancies in the material, which can be controlled by the sintering time.
authors.affiliation: Nano-Optical Property Laboratory and Department of Physics, Kyung Hee University, Seoul 130-701, South Korea.
authors.forename: Tae Jung
authors.initials: TJ
authors.lastname: Kim
authors.forename: Jae Jin
authors.initials: JJ
authors.lastname: Yoon
authors.forename: Soo Min
authors.initials: SM
authors.lastname: Hwang
authors.forename: Jun Hyuk
authors.initials: JH
authors.lastname: Choi
authors.forename: Soon Yong
authors.initials: SY
authors.lastname: Hwang
authors.forename: Tae Ho
authors.initials: TH
authors.lastname: Ghong
authors.forename: Nilesh
authors.initials: N
authors.lastname: Barange
authors.forename: Jun Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Young Dong
authors.initials: YD
authors.lastname: Kim
authors.forename: Jinho
authors.initials: J
authors.lastname: Joo