Regular Article

Effective performance improvement of organic thin film transistors with multi-layer modifications

¹ College of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, P.R. China
² Chongqing Normal University, Chongqing 400044, P.R. China
³ Institute of Photoelectronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, P.R. China

^* e-mail: zjl4062002@163.com

Received: 17 May 2020
Received in final form: 15 July 2020
Accepted: 11 August 2020
Published online: 18 September 2020

Abstract

Organic thin film transistors (OTFTs) based on dioctylbenzothienobenzothiophene (C8BTBT) and copper (Cu) electrodes were fabricated. For improving the electrical performance of the original devices, the different modifications were attempted to insert in three different positions including semiconductor/electrode interface, semiconductor bulk inside and semiconductor/insulator interface. In detail, 4,4′,4′′-tris[3-methylpheny(phenyl)amino] triphenylamine (m-MTDATA) was applied between C8BTBTand Cu electrodes as hole injection layer (HIL). Moreover, the fluorinated copper phthalo-cyanine (F₁₆CuPc) was inserted in C8BTBT/SiO₂ interface to form F₁₆CuPc/C8BTBT heterojunction or C8BTBT bulk to form C8BTBT/F₁₆CuPc/C8BTBT sandwich configuration. Our experiment shows that, the sandwich structured OTFTs have a significant performance enhancement when appropriate thickness modification is chosen, comparing with original C8BTBT devices. Then, even the low work function metal Cu was applied, a normal p-type operate-mode C8BTBT-OTFT with mobility as high as 2.56 cm²/Vs has been fabricated.