Probing the doping mechanisms and electrical properties of Al, Ga and In doped ZnO prepared by spray pyrolysis
File(s)
Accepted version
Author(s)
Maller, R
Porte, Y
Alshareef, H
McLachlan, MA
Type
Journal Article
Abstract
The measured structural, optical and electrical properties of Al, Ga and In doped ZnO
films deposited using spray pyrolysis are reported over the doping range 0.1 - 3 at%.
Over the entire doping series highly transparent, polycrystalline thin films are
prepared. Using AC Hall as a measurement technique we probe the electronic
properties of our doped films, deconvoluting the impact of doping on the measured
charge carrier concentrations and Hall mobility. We focus on the low doping range
i.e. 0.1 - 1 at%, where we observe unexpected variations in charge carrier
concentration and mobility and propose a mechanism to explain our observations. In
this doping range highly resistive films are formed hence we highlight AC Hall as a
reliable and highly reproducible technique for analysing electrical properties and
subsequently elucidate the doping mechanisms. The implementation of a simple,
post-deposition heat treatment demonstrated on our AZO results in typical films with
charge carrier concentrations exceeding > 1019 cm-3, and electron mobilities >
10 cm2
/Vs and stability exceeding 180 days. We describe in detail the nature of the
defect chemistry and the role of intrinsic defects and show, that despite significant
variations in dopant species and grain boundary concentrations, that the defect
chemistry dominates the electrical characteristics.
films deposited using spray pyrolysis are reported over the doping range 0.1 - 3 at%.
Over the entire doping series highly transparent, polycrystalline thin films are
prepared. Using AC Hall as a measurement technique we probe the electronic
properties of our doped films, deconvoluting the impact of doping on the measured
charge carrier concentrations and Hall mobility. We focus on the low doping range
i.e. 0.1 - 1 at%, where we observe unexpected variations in charge carrier
concentration and mobility and propose a mechanism to explain our observations. In
this doping range highly resistive films are formed hence we highlight AC Hall as a
reliable and highly reproducible technique for analysing electrical properties and
subsequently elucidate the doping mechanisms. The implementation of a simple,
post-deposition heat treatment demonstrated on our AZO results in typical films with
charge carrier concentrations exceeding > 1019 cm-3, and electron mobilities >
10 cm2
/Vs and stability exceeding 180 days. We describe in detail the nature of the
defect chemistry and the role of intrinsic defects and show, that despite significant
variations in dopant species and grain boundary concentrations, that the defect
chemistry dominates the electrical characteristics.
Date Issued
2016-07-07
Date Acceptance
2016-05-05
Citation
Journal of Materials Chemistry C, 2016, 4 (25), pp.5953-5961
ISSN
2050-7534
Publisher
Royal Society of Chemistry
Start Page
5953
End Page
5961
Journal / Book Title
Journal of Materials Chemistry C
Volume
4
Issue
25
Copyright Statement
This journal is © The Royal Society of Chemistry 2016
Sponsor
Engineering & Physical Science Research Council (E
Kaust
Grant Number
EP/K503733/1
N/A
Publication Status
Published
Date Publish Online
2016-05-24