Regular Article

Influence of underneath pentacene thickness on performance of p-n heterojunction organic thin film transistors

College of Communication Engineering, Chongqing University, 400044 Chongqing, P.R. China

^a e-mail: zjl4062002@163.com

Received: 20 November 2015
Revised: 24 January 2016
Accepted: 28 January 2016
Published online: 29 February 2016

Abstract

Organic thin film transistors (OTFTs) with heterojunction semiconducting layers composed of p-type pentacene and n-type fluorinated copper phthalocyanine (F₁₆CuPc) have been fabricated. The influence of pentacene film thickness on performance of transistors is carefully investigated. It has been found that, with the increase of pentacene film thickness, the electron mobility increases at first and then decreases intensely. But the shift of V_T is opposite comparing with electron mobility. The performance improvement can be attributed to the increase of free electron carriers by band bending at the pentacene/F₁₆CuPc interface, and better F₁₆CuPc film quality grown upon pentacene. Comparing with island growth-mode, layer-by-layer growth-mode of pentacene facilitates the growth of the upper F₁₆CuPc film.