Facile Electroless Deposition of Zinc Oxide Ultrathin Film for Zinc Acetate Solution-processed Transistors

Abstract

"A low-cost, ultra-thin, transparency and high-quality zinc oxide (ZnO) film was successfully demonstrated as the carrier transporting and semiconducting layer for thin-film transistor (TFT) devices. The ZnO ultra-thin film with 3.7 nm in thickness was spin-coated from zinc acetate sol-gel solution under electroless condition. The film structure was characterized by atomic force microscopy and x-ray diffraction spectroscopy, respectively. Among various processing temperatures, the electrical property of the fabricated TFT verified the devices could be successfully achieved from suitable annealing temperature of 300 to 700 degrees C. However, the higher treatment temperature of 800 to 900 degrees C deteriorated the transistor property due to the loss of oxygen vacancy. The electrical properties of these ZnO-based n-type TFTswere obtained as follows: the mobility (mu(sat))ranged from 0.47 to 1.78 cm(2) V-1 s(-1), the on/off current ratio ranged from 5.7 x 10(5) to 1.6 x 10(6), and the threshold voltage ranged from 9.7 to 17.3 V. The long-term (100 days) characterization for the evaluation of the ultra-thin ZnO TFT reliability on the mobility and on/off current ratio strongly suggested the effectiveness of solution-processed ultra-thin film transistors. This proposed efficient sol-gel solution method to fabricate transparent ZnO ultra-thin film was relatively simple and cost-effective technique, and could be used as a new candidate of material for next-generation electronic devices to meet the growing demand of small feature bioelectronic sensor, light emitting diode and flexible panel."