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Title: Local probe microscopic studies on Al-doped ZnO: Pseudoferroelectricity and band bending at grain boundaries

In this paper, based on piezoforce measurements, we show the presence of opposite polarization at grains and grain boundaries of Al-doped ZnO (AZO). The polarization can be flipped by 180° in phase by switching the polarity of the applied electric field, revealing the existence of nanoscale pseudoferroelectricity in AZO grown on Pt/TiO{sub 2}/SiO{sub 2}/Si substrate. We also demonstrate an experimental evidence on local band bending at grain boundaries of AZO films using conductive atomic force microscopy and Kelvin probe force microscopy. The presence of an opposite polarization at grains and grain boundaries gives rise to a polarization-driven barrier formation at grain boundaries. With the help of conductive atomic force microscopy, we show that the polarization-driven barrier along with the defect-induced electrostatic potential barrier account for the measured local band bending at grain boundaries. The present study opens a new avenue to understand the charge transport in light of both polarization and electrostatic effects.
Authors:
; ;  [1]
  1. SUNAG Laboratory, Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)
Publication Date:
OSTI Identifier:
22494861
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 1; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMIC FORCE MICROSCOPY; CHARGE TRANSPORT; DOPED MATERIALS; ELECTRIC FIELDS; FILMS; GRAIN BOUNDARIES; NANOSTRUCTURES; POLARIZATION; SILICON OXIDES; SUBSTRATES; TITANIUM OXIDES; ZINC OXIDES