ZnO is a transparent compound semiconductor with a wide band gap (3.37 eV) which can be grown as a polycrystalline thin film at room temperature. ZnO thin films, therefore, have received intensive interest for applications as a channel layer in transparent and flexible thin film transistors (TFTs). But, the high operating voltage of the ZnO based TFTs fabricated at a reduced temperature hinder its application in portable devices. The operating voltage can be reduced by using high dielectric constant materials as gate insulators. In this presentation, we report on dielectric and leakage current characteristics of room temperature deposited Bi_1.5Zn_1.0Nb_1.5O₇ (BZN) films on the basis of crystallographic structure and suitability of MgO coated BZN gate insulators as key building blocks in the fabrication of low voltage operating ZnO based thin-film transistors (TFTs). The MgO coated BZN gate insulator exhibited relatively high dielectric constant of 32 and low leakage current densities below 10^-8 A/cm² at an applied voltage of 5 V, which was an operating voltage of our TFTs. All room temperature processed ZnO based TFTs with MgO coated BZN gate dielectricshowed good saturation characteristics and low operation voltages (< 5 V) due to high dielectric constant (> 30) of MgO coated BZN gate dielectric. The field effect mobility and the on-off ratio were 5.5 cm²/Vs and 5×10⁵, respectively. The threshold voltage and subthreshold swing were 2 V and 0.35 V/dec, respectively. The room temperature processing, low operation voltage and high mobility of ZnO based TFTs with MgO coated gate insulator offer a promising route for the development of transparent and flexible electronics.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/7902 must be provided.

1. Mg-doped Ba_0.6Sr_0.4TiO₃ gate dielectrics for low voltage operating ZnO transparent transistor on polymer substrate