Jung Hyeon Bae

Carrier-suppressing effect of scandium in InZnO systems for solution-processed thin film transistors

The carrier-suppressing effect of Sc in InZnO systems was studied using thin-film transistors (TFTs) with a sol-gel processed active channel. As the amount of Sc content increased, the off current decreased, and the threshold voltage shifted to a positive bias region. The Sc effectively controlled the oxygen vacancies and supplied free electrons. X-ray photoelectron spectroscopy (XPS) verified that the vacancy-related oxygen 1s peak decreased with increasing Sc content. The TFT performance with 14% Sc showed that a field-effect mobility and on-off ratio were 2.06 cm2/V s and 8.02×106, respectively.

High-Performance Oxide Thin-Film Transistors Using a Volatile Nitrate Precursor for Low-Temperature Solution Process

Solution-processed InZnO (IZO) thin-film transistors (TFTs) are fabricated using a volatile metal nitrate precursor (Np) with annealing at 300^°C. Because the metal Np decomposes at low temperatures, metal oxide bonds were formed, and the organic residue in the oxide thin films was evaporated at low temperature. At 300^°C , the IZO thin films with Zn Np were of higher quality than those with Zn acetate precursor due to the reduced atomic disorder and evaporation of residual organics. The mobility of the IZO TFTs with Zn Np was 1.92 cm²/V·s at 300^°C annealing.

Thermite Reaction Between CuO Nanowires and Al for the Crystallization of a-Si

Nanoenergetic materials were synthesized and the thermite reaction between the CuO nanowires and the deposited nano-Al by Joule heating was studied. CuO nanowires were grown by thermal annealing on a glass substrate. To produce nanoenergetic materials, nano-Al was deposited on the top surface of CuO nanowires. The temperature of the first exothermic reaction peak occurred at approximately 600℃. The released heat energy calculated from the first exothermic reaction peak in differential scanning calorimetry, was approximately 1,178 J/g. The combustion of the nanoenergetic materials resulted in a bright flash of light with an adiabatic frame temperature potentially greater than 2,000℃. This thermite reaction might be utilized to achieve a highly reliable selective area crystallization of amorphous silicon films.

Memory effects of all-solution-processed oxide thin-film transistors using ZnO nanoparticles

Abstract— Non-volatile memory effects of an all-solution-processed oxide thin-film transistor (TFT) with ZnO nanoparticles (NPs) as the charge-trapping layer are reported. The device was fabricated by using a soluble MgInZnO active channel on a ZrHfOx gate dielectric. ZnO NPs were used as the charge-trapping site at the gate-insulator—channel interface, and Al was used for source and drain electrodes. Transfer characteristics of the device showed a large clockwise hysteresis, which can be used to demonstrate its memory function due to electron trapping in the ZnO NP charge-trapping layer. This memory effect has the potential to be utilized as a memory application on displays and disposable electronics.

Solution-processed oxide thin-film transistors using aluminum and nitrate precursors for low-temperature annealing

— In this article, a solution process for oxide thin-film transistors (TFTs) at low-temperature annealing was investigated. Solution-process engineering, including materials and precursors, plays an important role in oxide thin-film deposition on large glass and flexible substrates at low temperature. Reactive material could reduce the alloy reaction temperature for a multicomponent oxide system. A volatile precursor could also reduce annealing temperature in the formation of metal-oxide thin films. A solution process with reactive Al and a volatile nitrate precursor can demonstrates competitive oxide TFTs at 350°C.

P‐22: Memory Effects of Solution‐processed Oxide Thin‐Film Transistor using ZnO Nanoparticles

In this study, we report the study on the non-volatile memory effects of all solution-processed oxide thin film transistor (TFT) with ZnO nanoparticles (NPs) as the charge trapping layer. The transfer characteristics of the device showed a large clockwise hysteresis which can be used to demonstrate its memory function, due to electron trapping in the ZnO NPs charge-trapping layer.

New solid‐phase crystallization of amorphous silicon by selective area heating

Abstract A new crystallization method for amorphous silicon, called selective area heating (SAH), was proposed. The purpose of SAH is to improve the reliability of amorphous silicon films with extremely low thermal budgets to the glass substrate. The crystallization time shortened from that of the conventional solid‐phase crystallization method. An isolated thin heater for SAH was fabricated on a quartz substrate with a Pt layer. To investigate the crystalline properties, Raman scattering spectra were used. The crystalline transverse optic phonon peak was at about 519 cm‐1, which shows that the films were crystallized. The effect of the crystallization time on the varying thickness of the SiO2 films was investigated. The crystallization area in the 400nm‐thick SiO2 film was larger than those of the SiO2 films with other thicknesses after SAH at 16 W for 2 min. The results show that a SiO2 capping layer acts as storage layer for thermal energy. SAH is thus suggested as a new crystallization method for large‐area electronic device applications.