Investigation on Atomic Bonding Structure of Solution-Processed Indium-Zinc-Oxide Semiconductors According to Doped Indium Content and Its Effects on the Transistor Performance

Abstract

The atomic composition ratio of solution-processed oxide semiconductors is crucial in controlling the electrical performance of thin-film transistors (TFTs) because the crystallinity and defects of the random network structure of oxide semiconductors change critically with respect to the atomic composition ratio. Herein, the relationship between the film properties of nitrate precursor-based indium-zinc-oxide (IZO) semiconductors and electrical performance of solution-processed IZO TFTs with respect to the In molar ratio was investigated. The thickness, morphological characteristics, crystallinity, and depth profile of the IZO semiconductor film were measured to analyze the correlation between the structural properties of IZO film and electrical performances of the IZO TFT. In addition, the stoichiometric and electrical properties of the IZO semiconductor films were analyzed using film density, atomic composition profile, and Hall effect measurements. Based on the structural and stoichiometric results for the IZO semiconductor, the doping effect of the IZO film with respect to the In molar ratio was theoretically explained. The atomic bonding structure by the In doping in solution-processed IZO semiconductor and resulting increase in free carriers are discussed through a simple bonding model and band gap formation energy.

Investigation of Donor-like State Distributions in Solution-Processed IZO Thin-Film Transistor through Photocurrent Analysis

“…Furthermore, Figure 2 illustrates the behavior of the IZO TFTs at low, moderate, and high In molarity ratios, specifically 0.0125 M, 0.1 M and 0.2 M, respectively. More detailed electrical operation data concerning In molarity ratios are summarized in Supplementary Figure S2 and can be found in our previous study [37]. As shown in Figure 1, the currents remained consistent in the 1200-420 nm range regardless of the In concentration.…”

“…Additionally, Figure 3 depicts the photoelectrical characteristics corresponding to low, moderate, and high molarity ratios, respectively. The electrical parameters including the threshold voltage in terms of the In molarity ratio can also be found in our previous results [37]. The results based on the In molarity ratio are summarized in Supplementary Figure S3.…”

“…The 20 nm of Al source/drain electrodes deposited through thermal evaporation, with a width/length (W/L) ratio of 4000 µm/80 µm is shown in Figure 1a. The detailed fabrication processes and electrical characteristics can also be found in our previous studies [37]. In this approach, two calculation methods were used to analyze the photocurrent of the IZO TFT.…”

“…The 20 nm of Al source/drain electrodes deposited through thermal evaporation, with a width/length (W/L) ratio of 4000 µm/80 µm is shown in Figure 1a. The detailed fabrication processes and electrical characteristics can also be found in our previous studies [37]. Figure 1a shows a schematic of the photocurrent analysis system and provides an overview of the irradiation features used to characterize the electrical properties of IZO Figure 1a shows a schematic of the photocurrent analysis system and provides an overview of the irradiation features used to characterize the electrical properties of IZO TFT.…”

Improved Resistive Switching Characteristics and Synaptic Functions of InZnO/SiO2 Bilayer Device

“…3d 5/2 and 3d 3/2 are located at about 444.6 eV and 453.35 eV, respectively [67]. In addition, as shown in Figure 4c, the peak of O 1s at 529.6 eV represents metal-oxygen bonding, proving the existence of the IZO insulating layer [68]. Next, the Si-O bond is illustrated at an etch time of 25 s, as shown in Figure 4d,e.…”