Importance of Solvent Evaporation Temperature in Pre-Annealing Stage for Solution-Processed Zinc Tin Oxide Thin-Film Transistors

Abstract

We focused on the importance of solvent evaporation governed by the temperature of the pre-annealing stage (TS) in solution-processed zinc tin oxide (ZTO) thin-film transistors (TFTs). We controlled TS based on the boiling point (BP) of the solvent used. When TS reaches the BP, the field effect mobility is found to be about 1.03 cm2/V s, which is 10 times larger than the TS < Bp case (0.13 cm2/V s). The reason is presumed to be that residual organic defects are effectively removed as TS increases. In addition, when Ts is beyond Bp, the mobility is rather decreased due to structural defects such as pores and pinholes. Based on our results, it is noted that TS plays a significant role in the enhancement of electrical performance and stability of solution-processed ZTO TFTs.

A chemically treated IGZO-based highly visible-blind UV phototransistor with suppression of the persistent photoconductivity effect

“…75 In addition, the peaks at 285.9 eV, 288.4 eV, and 289.5 eV, corresponding to CO 3 2− , CO/C–OH, O–CO bonds, are associated with organic solvent residues. 76,77 Since the CO-related bonds also serve as defect sites in the bandgap that can induce the light absorption, 78 it is highly expected that IGZO with additives, which showed a decrease in trap states and organic solvent residues, can be utilized as a UV phototransistor that is immune to visible light.…”

Physico-Chemical Origins of Electrical Characteristics and Instabilities in Solution-Processed ZnSnO Thin-Film Transistors

“…Pre-annealing is a stage to form a solidified thin film by evaporating the solvent in the ZTO solution. When the pre-annealing temperature is too high, the roughness of the thin film is degraded, and pinholes or pore sites are formed, which can result in deterioration of electrical characteristics and bias stability [21]. Thus, we have optimized the pre-annealing temperature through our previous study [21].…”

“…When the pre-annealing temperature is too high, the roughness of the thin film is degraded, and pinholes or pore sites are formed, which can result in deterioration of electrical characteristics and bias stability [21]. Thus, we have optimized the pre-annealing temperature through our previous study [21]. After pre-annealing, the ZTO-deposited Si/SiO 2 wafers were annealed at 500 • C in air for 1 h in a tube furnace.…”

“…The annealing temperature differs depending on the precursor, metal cation, and solvent. The desirable annealing temperature for ZTO TFTs used in this study was obtained through the study of reported articles and our TFT experiments [3,14,15,21]. For the source and drain electrodes, 50 nmthick aluminum was deposited on the ZTO semiconductors using a thermal evaporator.…”