Inkjet-printed p-type tellurene and n-type MoS2 transistors for CMOS electronics

Abstract

Abstract Two-dimensional semiconductor materials combine exceptional electronic transport properties with mechanical flexibility and hence can be an ideal choice for large-area flexible and wearable electronics. While inkjet printing may be a suitable approach to fabricate high throughput electronic components on polymer substrates, solution-processed 2D semiconductor network transistors suffer from two major hindrances: extremely high inter-flake resistance and the lack of high-performance p-type semiconductors. This study shows that inkjet-printed tellurium nanowires or tellurene nanoflakes can offer high-performance p-type TFTs with current density up to 100 μA/μm and an On-Off ratio >105. In order to circumvent the high inter-flake junction resistance, a narrow-channel, near-vertical device architecture has been used that ensures predominantly intra-flake/ intra-nanowire transport, which resulted in three orders of magnitude increase in the current density compared to conventional devices without compromising on the On-Off ratio. Moreover, we show the whole device operation within ± 2 V, with a threshold voltage close to 0 V. The complete device fabrication is carried out at room temperature, thereby making it compatible with inexpensive polymer substrates. Next, outstanding device performance has also been realized with electrochemically-exfoliated and inkjet-printed n-type MoS2 TFTs, demonstrating a current density of 60 μA/μm and an On-Off ratio of 106. Furthermore, we show tellurene-based p-type depletion-load unipolar inverters and CMOS inverters alongside n-type MoS2 TFTs, demonstrating a signal gain of 12 and 11, respectively. The CMOS inverters are found to operate at a frequency of 1 kHz.