Power-efficient and high-performance potential of pentacene transistors enabled by metal-nitride gate insulators fabricated with nitrogen plasma

• Published in: Organic electronics 2024-05, Vol.128, p.107034, Article 107034
• Main Authors: Wang, Yu Wu, Selvaraj, Pravinraj, Cheng, Yu Han, Chen, Zheng Han, Chi, Ming Han
• Format: Article
• Language: English
• Subjects: Metal-nitride; Organic electronics; Plasma reaction; Power consumption; Threshold voltage
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2024.107034

The demand for next-generation organic field-effect transistors (OFETs) with low operating voltage is becoming gradually attractive in many application areas, such as flexible/wearable medical sensors and stretchable electronics. While using high dielectric materials is a potent approach, it often results in a decline in field-effect mobility or on/off ratio. Unfortunately, achieving low-voltage operation has hindered practical applications, compromising device performance. Here, we discovered for the first time a novel class of low-driving voltage pentacene transistors adopting gate insulators composed of nitrogen-plasma-reacted AlNx, TiNx, and TaNx. This exciting discovery is simple, affordable, environmentally friendly, and secure. X-ray photoelectron spectrometer (XPS) analysis reveals that the as-formed metal nitrides are composited with certain native oxide components, exhibiting outstanding leakage current blocking capacity and a high dielectric constant. Further, the surface energy of metal nitrides was altered by applying a thin layer of poly-(4-vinylphenol) (PVP). This modification improved the growth of pentacene grains and the insulator/pentacene interface. The best devices by comprehensive evaluation, the TiNx samples, achieve a high average of field-effect mobility ∼1.41 cm2/Vs, a subthreshold swing of 0.19 V/dec, an on/off current ratio of ∼104, and a turn-on voltage close to 0 V, which shows promising potential candidates for the flexible electronic devices, optoelectronic devices, and neuromorphic application. A nitrogen-plasma reacted metal-oxide/ poly-(4-vinylphenol) exhibits a high relative dielectric constant (k) (∼10). The hybrid gate insulators are used successfully in low-voltage OFETs. The TiNx/PVP samples achieve a high average of field-effect mobility ∼1.41 cm2/Vs and a turn-on voltage close to 0 V, which shows promising potential candidates for flexible electronic devices, optoelectronic devices, and neuromorphic applications. [Display omitted] •High-performance and low-driving voltage pentacene transistors are realized.•Nitrogen-plasma-reacted metal-nitrides are involved in gate insulator fabrication.•Devices composed of AlNx, TiNx, and TaNx are comprehensively studied.•The reacted metal nitride is verified to possess native oxide.