A Low-Temperature Solution-Process High-k Dielectric for High-Performance Flexible Organic Field-Effect Transistors

Abstract

Applying high-k dielectrics can effectively reduce the operating voltage of Organic fieldeffect transistors (OFETs) to a few volts, thus significantly miniaturizing the dynamic power consumption of OFETs. Aluminum oxide is a promising dielectric material due to its high permittivity (k 6-9). In this work, a simple, low-cost, low-temperature (only 85°C) solution process is used to prepare amorphous AlO x dielectric thin films for high-performance flexible OFET applications. The AlO x thin film was spin-coated and then solidified using deep ultraviolet irradiation without high-temperature annealing. The as-deposited AlO x thin film has a root mean square surface roughness of 0.47 nm and maintains a very low leakage current density of 8 × 10-9 A/cm 2 at 3.5 MV/cm and high dielectric constant of about 8.3 (at 1 kHz). The complete OFET based on this dielectric can operate at a 3 V gate bias with saturation mobility of 1.8 cm 2 /Vs, and steep sub-threshold swing of 110 mV/dec. Our work demonstrated a low-temperature solution process to fabricate a high-k metal oxide dielectric for low-power OFET applications.

High-performance ultra-low-voltage organic field-effect transistors based on anodized TiOx dielectric and solution-sheared organic single crystals

“…15 P dyn can be efficiently decreased by reducing the gate-source voltage (V G ) of the OFET because it is proportional to the square of V G . 15 Therefore, considerable effort has been made to successfully reduce the V G within the dry battery range (B3 V) by applying high-k dielectrics, including metal oxides, [16][17][18][19] and ferroelectric co-polymers. [20][21][22][23] Although a 3 V device has a significantly lower P dyn value than a device based on a SiO 2 dielectric, there is still an opportunity to further reduce the P dyn according to the square law of V G .…”

Low-voltage organic single-crystal field-effect transistors and inverters enabled by a solution processable high-kdielectric

“…[13][14][15][16] Several critical properties such as high-permittivity (high-k) for low voltage operation, dense and smooth surface for the low gate leakage current, and minimal interface state density for stable operation are the premise for the low power consumption of OFETs. 17 To this end, tremendous efforts have been devoted to developing novel high-k dielectrics for low-voltage OFETs, including AlO x , 18 HfO x , 19 and ZrO x . 20 However, a prominent problem is that most low-voltage OFETs based on these high-k dielectrics show substantial mobility reduction, commonly exhibiting over 80% lower than those using octadecyltrichlorosilane (OTS)modified SiO 2 dielectrics (Table S1, ESI †).…”

Single-crystalline silicon nanomembrane thin-film transistors with anodized aluminum oxide as a gate dielectric on rigid and flexible substrates

“…However, these dielectric materials suffer from poor quality and a low dielectric constant. High-dielectric-constant dielectrics (high-k), such as Al 2 O 3 HfO 2 , ZrO 2 , Ta 2 O 5 , and Lu 2 O 3 , etc, have been widely investigated to replace SiO 2 as gate dielectricsin TFTs in recent years [16][17][18][19][20][21][22][23][24][25][26]; nevertheless, most dielectric layers are processed using costly and sophisticated techniques such as pulsed laser deposition, CVD, and atomic layer deposition, etc. In addition to the requirements of complex mechanical equipment, the required processing temperature is usually over 300 • C for high-quality dielectrics, which exceeds the maximum temperature that most flexible substrates can sustain.…”