Organic base modulation triodes and their inverters on flexible substrates

A vertical-type transistor, organic base modulation triode (OBMT), which is fabricated employing two back-to-back diodes on a flexible plastic substrate, was investigated. The substrates were precleaned using detergent, acetone, isopropyl alcohol, and treated with an UV-ozone cleaner for 15 min. A Au layer 30nm thick was deposited on the glass or PET substrate as the collector electrode. A thin Al layer was deposited as the base layer, and a LiF layer of 0.4nm was thermally evaporated as the carrier-injection enhancement layer. Subsequently, a 20 nm thick NPB layer was thermally evaporated to enhance the carrier energy, and a pentacene layer 140 nm thick was thermally evaporated. All organic materials and metal electrodes were deposited in a thermal-evaporation chamber at a base pressure of 10^-6 Torr. The OBMT shows a high output current with an apparent saturation region at low voltages.