Achieving ultralow contact resistance in copolymer organic transistors via a solution-processed dopant-assisted modification layer for tunneling injection enhancement

H Hengdian Chang (College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,) J Jun Zhang S Shuiqi Liu (College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,) H Haonan Lin (Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and Technology Shenzhen China) H Haowen Qian (State Key Laboratory of Flexible Electronics (LoFE) & Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NJUPT) 3 , Nanjing 210023,) J Jiafei Yao (College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,) K Kemeng Yang (College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,) J Jing Chen M Man Li W Wen Li H Haifeng Ling M Mingdong Yi (State Key Laboratory of Flexible Electronics (LoFE) & Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NJUPT) 3 , Nanjing 210023,) Y Yufeng Guo

Abstract

The challenge of achieving Ohmic contacts fundamentally limits the performance of organic electronic devices, primarily due to high contact resistance resulting from Schottky contact at the metal–organic semiconductor contact interface. This study demonstrates a general strategy to significantly diminish contact resistance in copolymer organic field-effect transistors (OFETs) by achieving a quasi-Ohmic contact where the dominant mechanism is tunneling injection rather than thermionic emission. By introducing a solution-processed dopant-assisted modification (DAM) layer fabricated via simple orthogonal solvent processing at the interface, a heavily doped interfacial region is created. This region dramatically narrows the Schottky barrier width, enabling efficient charge injection via the tunneling injection enhancement effect. An optimized DAM layer achieves an ultralow contact resistance of 66 Ω cm, representing an 85% reduction vs the conventional device. Concurrently, the field-effect mobility increases by 273% to 1.68 cm2 V−1 s−1, while the threshold voltage decreases by 36% to −9.37 V. The DAM layer exhibits broad applicability and good stability, while also showing potential for flexible OFETs. This study provides a simple and universal interfacial engineering pathway to high-performance organic transistors, paving the way for advanced organic integrated circuits.

Article Details

Volume / Issue Vol. 129, Issue 3
Published July 20, 2026
ISSN 0003-6951
Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (13)

H

Hengdian Chang

College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,

J

Jun Zhang

S

Shuiqi Liu

College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,

H

Haonan Lin

Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and Technology Shenzhen China

H

Haowen Qian

State Key Laboratory of Flexible Electronics (LoFE) & Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NJUPT) 3 , Nanjing 210023,

J

Jiafei Yao

College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,

K

Kemeng Yang

College of Integrated Circuit Science and Engineering, National & Local Joint Engineering Laboratory for RF Integration and Micro-packaging Technologies, Nanjing University of Posts and Telecommunications 1 , No. 9 Wenyuan Rd., Nanjing,

J

Jing Chen

M

Man Li

W

Wen Li

H

Haifeng Ling

M

Mingdong Yi

State Key Laboratory of Flexible Electronics (LoFE) & Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NJUPT) 3 , Nanjing 210023,

Y

Yufeng Guo