Low-Voltage Organic Field-Effect Transistor With PMMA/$ \hbox{ZrO}_{2}$ Bilayer Dielectric

Abstract

This paper reports on the application of a bilayer polymethylmethacrylate (PMMA)/ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> dielectric in copper ph-thalocyanine (CuPc) organic field-effect transistors (OFETs). By depositing a PMMA layer on ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , the leakage of the dielectric is reduced by one order of magnitude compared to single- layer ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . A high-quality interface is obtained between the organic semiconductor and the combined insulators. By integrating the advantages of polymer and high-fe dielectrics, the device achieves both high mobility and low threshold voltage. The typical field-effect mobility, threshold voltage, on/off current ratio, and subthreshold slope of OFETs with bilayer dielectric are 5.6 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V ldr s, 0.8 V, 1.2 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , and 2.1 V/dec, respectively. By using the bilayer dielectrics, the hysteresis observed in the devices with single-layer ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is no longer present.