Tailoring the Dielectric Layer Structure for Enhanced Performance of Organic Field-Effect Transistors: The Use of a Sandwiched Polar Dielectric Layer

Shijiao Han; Xin Yang; Xinming Zhuang; Junsheng Yu; Lu Li

doi:10.3390/ma9070545

Tailoring the Dielectric Layer Structure for Enhanced Performance of Organic Field-Effect Transistors: The Use of a Sandwiched Polar Dielectric Layer

Materials (Basel). 2016 Jul 7;9(7):545. doi: 10.3390/ma9070545.

Authors

Shijiao Han¹, Xin Yang², Xinming Zhuang³, Junsheng Yu^{4

5}, Lu Li⁶

Affiliations

¹ State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China. hanshijiao@outlook.com.
² Co-Innovation Center for Micro/Nano Optoelectronic Materials and Devices, Research Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China. yangx@cqwu.edu.cn.
³ State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China. xmzhuang@std.uestc.edu.cn.
⁴ State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China. jsyu@uestc.edu.cn.
⁵ Co-Innovation Center for Micro/Nano Optoelectronic Materials and Devices, Research Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China. jsyu@uestc.edu.cn.
⁶ Co-Innovation Center for Micro/Nano Optoelectronic Materials and Devices, Research Institute for New Materials and Technology, Chongqing University of Arts and Sciences, Chongqing 402160, China. lli@cqwu.edu.cn.

Abstract

To investigate the origins of hydroxyl groups in a polymeric dielectric and its applications in organic field-effect transistors (OFETs), a polar polymer layer was inserted between two polymethyl methacrylate (PMMA) dielectric layers, and its effect on the performance as an organic field-effect transistor (OFET) was studied. The OFETs with a sandwiched dielectric layer of poly(vinyl alcohol) (PVA) or poly(4-vinylphenol) (PVP) containing hydroxyl groups had shown enhanced characteristics compared to those with only PMMA layers. The field-effect mobility had been raised more than 10 times in n-type devices (three times in the p-type one), and the threshold voltage had been lowered almost eight times in p-type devices (two times in the n-type). The on-off ratio of two kinds of devices had been enhanced by almost two orders of magnitude. This was attributed to the orientation of hydroxyl groups from disordered to perpendicular to the substrate under gate-applied voltage bias, and additional charges would be induced by this polarization at the interface between the semiconductor and dielectrics, contributing to the accumulation of charge transfer.

Keywords: dielectric/semiconductor interface; hydroxyl group; organic field-effect transistors (OFETs); polar dielectric material.