Characterization on Bandedge Electronic Structure of MgO Added Bi1.5Zn1.0Nb1.5O7 Gate Dielectrics for ZnO-Thin Film Transistors

Abstract

Significantly reduced leakage current characteristics of the Bi1.5Zn1.0Nb1.5O7 (BZN) gate dielectric for producing high-performance ZnO-thin film transistors (TFTs) were achieved by an addition of MgO (30 atom %). The overall TFT parameters using MgO-BZN gate insulator against those that used pure BZN dielectric were enhanced remarkably. The diphasic MgO-BZN composite oxide structure was confirmed by an analysis of the spectroscopically detected bandedge electronic structures. The bandgap energy of MgO-BZN was identical to that of BZN at similar to 3.3 eV, but the Fermi energy level was shifted to 1.2 eV from 0.6 eV for BZN against the valence bandedge. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3508481] All rights reserved.