Energy-dependent relaxation time in quaternary amorphous oxide semiconductors probed by gated Hall effect measurements

Josephine Socratous, Shun Watanabe, Kulbinder K. Banger, Christopher N. Warwick, Rita Branquinho, Pedro Barquinha, Rodrigo Martins, Elvira Fortunato, and Henning Sirringhaus
Phys. Rev. B 95, 045208 – Published 18 January 2017
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Abstract

Despite the success of exploiting the properties of amorphous oxide semiconductors for device applications, the charge transport in these materials is still not clearly understood. The observation of a definite Hall voltage suggests that electron transport in the conduction band is free-electron-like. However, the temperature dependence of the Hall and field-effect mobilities cannot be explained using a simple bandlike model. Here, we perform gated Hall effect measurements in field-effect transistors, which allow us to make two independent estimates of the charge carrier concentration and determine the Hall factor providing information on the energy dependence of the relaxation time. We demonstrate that the Hall factor in a range of sputtered and solution-processed quaternary amorphous oxides, such as a-InGaZnO, is close to two, while in ternary oxides, such as InZnO, it is near unity. This suggests that quaternary elements like Ga act as strong ionized impurity scattering centers in these materials.

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  • Received 2 March 2016
  • Revised 19 September 2016

DOI:https://doi.org/10.1103/PhysRevB.95.045208

©2017 American Physical Society

Physics Subject Headings (PhySH)

  1. Research Areas
  1. Physical Systems
Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Josephine Socratous1, Shun Watanabe1,2,3, Kulbinder K. Banger1, Christopher N. Warwick1, Rita Branquinho4, Pedro Barquinha4, Rodrigo Martins4, Elvira Fortunato4, and Henning Sirringhaus1,*

  • 1Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
  • 2Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8561, Chiba, Japan
  • 3JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
  • 4i3N/CENIMAT, Department of Materials Science, Faculty of Science and Technology, Universidade NOVA de Lisboa and CEMOP/UNINOVA, Campus de Caparica, 2829-516 Caparica, Portugal

  • *Corresponding author: hs220@cam.ac.uk

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Issue

Vol. 95, Iss. 4 — 15 January 2017

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