Nanoscale flexible organic thin-film transistors

Abstract

Direct-write electron-beam lithography has been used to fabricate low-voltage p-channel and n-channel organic thin-film transistors with channel lengths as small as 200 nm and gate-to-contact overlaps as small as 100 nm on glass and on flexible transparent polymeric substrates. The p-channel transistors have on/off current ratios as large as 4 × 10 9 and subthreshold swings as small as 70 mV/decade, and the n-channel transistors have on/off ratios up to 10 8 and subthreshold swings as low as 80 mV/decade. These are the largest on/off current ratios reported to date for nanoscale organic transistors. Inverters based on two p-channel transistors with a channel length of 200 nm and gate-to-contact overlaps of 100 nm display characteristic switching-delay time constants between 80 and 40 ns at supply voltages between 1 and 2 V, corresponding to a supply voltage–normalized frequency of about 6 MHz/V. This is the highest voltage-normalized dynamic performance reported to date for organic transistors fabricated by maskless lithography.

Progress in Data Acquisition of Wearable Sensors

“…In addition to the OTFT based on the printing process, Ute Zschieschang et al proposed an OTFT based on the electron beam lithography process [ 37 ]. This OTFT has three parts ( Figure 3 (ci)), a patterned aluminum gate, gold source, and gold drain; an aluminum oxide (AlO x ) dielectric; and a phosphonic acid self-assembled monolayer (SAM).…”

“…The high on/off current ratio indicates the high electron mobility of this OTFT, while the high subthreshold swing indicates that this OTFT switches rapidly between the on and light states. As of April 2022, it has the largest on/off current ratio among nanoscale OTFTs [ 37 ].…”

A Sub‐20 nm Organic/Inorganic Hybrid Dielectric for Ultralow‐Power Organic Thin‐Film Transistor (OTFT) With Enhanced Operational Stability

“…[ 1–4 ] A number of materials and devices have been suggested, and the OTFT performance has been enhanced remarkably in the last 2 decades. [ 5,6 ] With such efforts, various kinds of functional electronic devices based on OTFTs have been demonstrated, including integrated circuits (ICs), [ 7,8 ] flash memories, [ 9,10 ] neuromorphic devices, [ 11,12 ] and sensors. [ 13,14 ]…”

“…[ 16,17 ] Along this line, various types of organic and inorganic hybrid dielectric materials have been investigated extensively to exploit the advantages from both organic and inorganic dielectric materials. [ 6,18–38 ] For example, inorganic dielectric materials such as aluminum oxide (AlO x ) and hafnium oxide (HfO x ) generally exhibited high dielectric constant as well as outstanding dielectric strength. [ 39 ] However, the abundant amount of hydroxyl groups on the surface of the oxide layer often generates unwanted trap sites, which thus impair the OTFT performance.…”

“…[1][2][3][4] A number of materials and devices have been suggested, and the OTFT performance has been enhanced remarkably in the last 2 decades. [5,6] With such efforts, various kinds of functional electronic devices based on OTFTs have been demonstrated, including integrated circuits (ICs), [7,8] flash memories, [9,10] neuromorphic devices, [11,12] and sensors. [13,14] Gate dielectric plays a crucial role in the reliable operation of OTFTs by blocking unwanted leakage current while accumulating charge carriers at the interface with organic semiconductor layers.…”