Low Contact Resistance Organic Single‐Crystal Transistors with Band‐Like Transport Based on 2,6‐Bis‐Phenylethynyl‐Anthracene

• Published in: Advanced science Vol. 11; no. 22; pp. e2400112 - n/a
• Main Authors: Sun, Yanan, Shi, Xiaosong, Yu, Yamin, Zhang, Zhilei, Wu, Miao, Rao, Limei, Dong, Yicai, Zhang, Jing, Zou, Ye, You, Shengyong, Liu, Jie, Lei, Ming, Liu, Chuan, Jiang, Lang
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.06.2024; John Wiley and Sons Inc; Wiley
• Subjects: contact resistance; Energy consumption; organic field‐effect transistors; Scanning electron microscopy; Semiconductors; Single crystals; single‐crystal; Transistors; single‐crystal; contact resistance; organic field‐effect transistors
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202400112

Contact resistance has become one of the main bottlenecks that hinder further improvement of mobility and integration density of organic field‐effect transistors (OFETs). Much progress has been made in reducing contact resistance by modifying the electrode/semiconductor interface and decreasing the crystal thickness, however, the development of new organic semiconductor materials with low contact resistance still faces many challenges. Here, 2,6‐bis‐phenylethynyl‐anthracene (BPEA) is found, which is a material that combines high mobility with low contact resistance. Single‐crystal BEPA OFETs with a thickness of ≈20 nm demonstrated high mobility of 4.52 cm2 V−1 s−1, contact resistance as low as 335 Ω cm, and band‐like charge transport behavior. The calculated compatibility of the EHOMO of BPEA with the work function of the Au electrode, and the decreased |EHOMO‐ΦAu| with the increase of external electric field intensity from source to gate both contributed to the efficient charge injection and small contact resistance. More intriguingly, p‐type BPEA as a buffer layer can effectively reduce the contact resistance, improve the mobility, and meanwhile inhibit the double‐slope electrical behavior of p‐channel 2,6‐diphenyl anthracene (DPA) single‐crystal OFETs. OFETs based on BPEA single crystals are fabricated with an ultralow contact resistance of 335 Ω cm and band‐like transport. In addition, the introduction of BPEA thin films (6 nm) can greatly improve the charge injection and reduce the contact resistance of DPA single crystal devices despite the increase of the functional layer thickness, and thus improve the mobility.