Polydopamine–Copper Hybrid Films as Source and Drain for Oxide Semiconductor Field‐Effect Transistors

• Published in: Advanced electronic materials Vol. 4; no. 8
• Main Authors: Namgung, Seok Daniel, Lee, Jaehun, Sung, Taehoon, Kim, Hyung‐Jun, Cho, Ah‐Jin, Koh, Sungjoon, An, Junghyun, Choe, Ik Rang, Nam, Ki Tae, Kwon, Jang‐Yeon
• Format: Journal Article
• Language: English
• Published: 01.08.2018
• Subjects: field‐effect transistors; flexible transparent electrodes; oxide semiconductors; polydopamine–Cu; pyrolysis
• ISSN: 2199-160X; 2199-160X
• DOI: 10.1002/aelm.201800046

Oxide semiconductors are one of the key components for flexible and transparent electronics, but their use has been limited by the work function of contact materials. Carbon‐based materials are strong candidates for flexible transparent electrodes, and nitrogen‐doped carbon materials have been specifically investigated due to the controllability of their work function. Of the many methods to dop nitrogen, the pyrolysis of biomolecules is a particular focus since it is a simple, inexpensive process that yields a high atomic percent of nitrogen. Polydopamine (pDop), which is inspired by adhesive proteins in mussels, has been suggested for use as a precursor for pyrolysis, and the pyrolyzed pDop–Cu hybrid film shows the lowest resistivity (1.4 × 10−4 Ω cm) in pyrolyzed carbon so far, for which copper chelation is attributed to reduction in resistivity. The pyrolyzed film also shows a transparency of 84%, and it is stable in cyclic bending tests up to 105 cycles. The films are further applied to the source and drain of a field‐effect transistor, and the devices achieve a high performance that is comparable to that from molybdenum contacted device, with the work function ranging from 4.51 to 4.31 eV. A new polydopamine (pDop)–Cu hybrid film as source and drain of oxide semiconductor field effect transistors is obtained. The device incorporating hybrid film shows high performance comparable to molybdenum based devices, in which device performance is interpreted as the work function of pyrolyzed pDop–Cu ranging from 4.31 to 4.59 eV.