[TuP3G] Oxide Materials & Devices

[TuP3G-07] Low-temperature Atomic Layer Deposition of ZnO Thin Film Enabling Optoelectronic Synaptic Behavior

〇JunHyeong Park¹, JungBeen Cho¹, SeungMin Song¹, Seyeon Tak¹, Sung-Nam Lee¹ (1. TUKorea (Korea))

ZnO films were grown on sapphire substrates by atomic layer deposition below 100 °C, and optoelectronic synaptic devices with Al electrodes were fabricated. As the growth temperature decreased from 90°C to 40°C, surface roughness decreased from 2.9nm to 0.07nm, indicating a transition from polycrystalline to amorphous structures. Deep-level emission near 550nm increased, while dark current was decreased. The highest photocurrent under 365 nm UV illumination was observed at 90°C. Paired-pulse facilitation (PPF) measurements showed that as the growth temperature decreased from 90°C to 40°C, PPF at Δt=1.0s increased from 184% to 220%. However, at Δt>10s, the PPF increased from 168% to 175% as growth temperature decreased from 90°C to 55°C, but decreased sharply to 153% for the device grown at 40°C. These results indicate that ZnO-based optoelectronic synaptic devices grown below 100°C exhibit stable photoinduced currents and reliable memory characteristics.