Liang Xiaoci, Liu Ling, Cai Guangshuo, Yang Peng, Pei Yanli, Liu Chuan
The State Key Laboratory of Optoelectronic Materials and Technologies and the Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, People's Republic of China.
Department of Electronic Communication and Technology, Shenzhen Institute of Information Technology, Shenzhen 518172, People's Republic of China.
J Phys Chem Lett. 2020 Apr 2;11(7):2765-2771. doi: 10.1021/acs.jpclett.0c00583. Epub 2020 Mar 24.
In developing low-power electronics, low-voltage transistors have been intensively investigated. One of the most important findings is that some high- oxide gate dielectrics can lead to remarkable enhancement of apparent mobility in thin-film transistors (TFTs), which is not clearly understood. Here, we investigate InO TFTs with solution-processed AlO dielectrics. At very low frequencies (<1 Hz), the AlO films feature strong voltage-dependent capacitance. Also, cyclic voltammograms show clear features of surface-controlled Faradaic charge transfer. The two independent experiments both point to the formation of pseudocapacitance, which is similar to the mechanism behind some supercapacitors. A physical model including charge transfer is established to describe ion distribution. The charge transfer is probably related to residual hydrogens, as revealed by secondary-ion mass spectroscopy. The results provide direct evidence of the formation of pseudocapacitance in TFTs with high apparent mobilities and advance the understanding of mechanisms, measurements, and applications of such TFTs for low-power electronics.
