Room‐Temperature Fabrication of High‐Quality Lanthanum Oxide High‐κ Dielectric Films by a Solution Process for Low‐Power Soft Electronics

High-quality dielectric films are indispensable for field-effect electronic devices to provide high electrical performance. However, deposition of high-quality dielectric films on flexible substrate remains a challenging task, which greatly limits the electrical performance of flexible or organic field-effect devices. A room-temperature deep ultraviolet (DUV) irradiation process is proposed for densification of solution-processed La2O3 films. It is found that room-temperature DUV-La2O3 films not only exhibit leakage and dielectric properties that are comparable to those of high-temperature annealed-La2O3 films, but also have very smooth and clean surfaces and excellent bending strain tolerance. The fabricated La2O3 films exhibit a wide band gap (5.78 eV), high dielectric constant (12.68), low leakage density (8.8 x 10(-7) A cm(-2) at 2 MV cm(-1)), and high breakdown field strength (3.5 MV cm(-1)). Organic thin-film transistors (OTFTs) based on high-quality solution-processed La2O3 gate dielectrics show a low operation voltage (<= 3 V), low gate leakage current (<10(-9) A), and high I-on/I-off ratio (>10(5)). Based on these room-temperature-fabricated high-performance OTFTs, low-voltage complementary integrated circuits are successfully fabricated, including complementary inverters and NAND gate circuits. The results demonstrate that room-temperature DUV-processed La2O3 films are ideal gate dielectric materials for future flexible and low-power-consumption electronic devices.