Hyeonjun Kong | Searcharxiv

arXiv2025

Indium Hydroxide Ceramic Targets: A Breakthrough in High-Mobility Thin-Film Transistor Technology

Thin-film transistors composed of a hydrogen-containing indium oxide active layer are promising candidates for backplane devices in next-generation flat panel displays, offering higher definition and faster operation. However, the hydrogen incorporation process during film deposition poses challenges for scalable and industrial development due to both safety and controllability issues. Here, we demonstrate that using indium hydroxide ceramic as the target material for film deposition overcomes the difficulties associated with hydrogen gas usage. We sintered commercially available indium hydroxide powder using a conventional ceramic process at 150-250{\deg}C in air and utilized it for the deposition of hydrogen-incorporated indium oxide films via pulsed laser deposition. The resulting indium oxide films, after thermal annealing, contained a sufficient concentration of hydrogen and exhibited very high electron mobility due to significantly grown grains. Furthermore, we confirmed that the fabricated thin-film transistors exhibited comparably high performance to those produced using the gas-phase hydrogen incorporation method. This approach offers a practical pathway for hydrogen-containing indium oxide-based thin-film transistors in next-generation flat panel displays.

cond-mat.mtrl-sci↗

arXiv2024

High-performance solid-state electrochemical thermal switches with earth-abundant cerium oxide

Thermal switches, which electrically turn heat flow on and off, have attracted attention as thermal management devices. Electrochemical reduction/oxidation switches the thermal conductivity (\k{appa}\) of active metal oxide films. The performance of the previously proposed electrochemical thermal switches is low; on/off \k{appa}\-ratio is mostly less than 5 and \k{appa}\-switching width is less than 5 W/mK. We used CeO2 thin film as the active layer deposited on a solid electrolyte YSZ substrate. When the CeO2 thin film was reduced once (off-state) and then oxidized (on-state), \k{appa}\ was about 2.2 W/mK in the most reduced state, and \k{appa}\ increased with oxidation to 12.5 W/mK (on-state). This reduction (off-state)/oxidation (on-state) cycle was repeated 100 times and the average value of \k{appa}\ was 2.2 W/mK after reduction (off-state) and 12.5 W/mK after oxidation (on-state). The on/off \k{appa}\-ratio was 5.8 and \k{appa}\-switching width was 10.3 W/mK. The CeO2-based solid-state electrochemical thermal switches would be potential devices for thermal shutters and thermal displays.

cond-mat.mtrl-sci↗