Thin-film Electronics based on van der Waals materials and their applications
Yen-Fu Lin1*
1Physics, National Chung Hsing University, Taichung, Taiwan
* Presenter:Yen-Fu Lin,
Most van der Waals-based electronics have confronted with severe oxidation, discernible surface morphological variations, disturbed carrier transport, and subsequently significant performance degradation under ambient atmosphere owing to their acknowledged environmental sensitivity, including black phosphorus, indium selenide (InSe), hafnium sulfide, and molybdenum ditelluride. Lots of pioneering works have been devoted to passivation engineering to achieve both good air stability and electrical performance. In this talk, layered InSe materials have been explored. In the first part, layered InSe electronics with superior controlled stability are reported and demonstrated by depositing an In doping layer. And the optimized InSe electronics can deliver unprecedented high electron mobility up to 3700 cm²/V-S in vacuum at room temperature. The related flexibilities in both logic-circuit and triboelectric applications have been further done, such as inverter, NAND, NOR, and touch devices.[1, 2] In the second part. it is found that if our InSe electronics are stored under ambient conditions, a 2-nm-thick native InOx, located at the bottom of the layered InSe channel, is capable of boosting the charge trapping events in the InSe electronics. Such the innate charge trapping layer with charge-controllable capability empowers this simplified configuration to perform reliable memory operations with outstanding durability and multilevel storage characters. The native oxide-boosted InSe electronic is employed to imitate the essential synaptic functions from short-term plasticity of paired-pulse facilitation to long-term plasticity of spike-timing-dependent plasticity in device level, as well as the system-level pattern recognition of the designed artificial neural network.[3] In the end part, through a substrate-tunable trapping effect, we further develop a unique synaptic behavior, i.e. inverse paired-pulse facilitation, in our layered InSe electronics.[4, 5] In all of our experimental results, we believed that our new findings pave a significant avenue for developing next-generation electronics using 2D InSe materials.

[1]. Adv. Mater. 30, 1803690, (2018)
[2]. Adv. Funct. Mater. 29, 1809119 (2019)
[3]. Nat. Commun. 11, 2972 (2020)
[4]. Nano Energy 77, 105258 (2020)
[5]. NPJ 2D Mater. Appl. 5, 60 (2021)

Keywords: InSe, layered electroncis, artificial synapse