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, Pedro Barquinha, Rodrigo Martins, Elvira Fortunato, Henning Sirringhaus, Rita Branquinho

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

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.

Original languageEnglish
Article number045208
JournalPhysical Review B
Volume95
Issue number4
DOIs
Publication statusPublished - 18 Jan 2017

Keywords

  • THIN-FILM TRANSISTORS
  • LOW-TEMPERATURE
  • DISORDERED-SYSTEMS
  • MOBILITY
  • FABRICATION
  • CONDUCTION
  • SCATTERING
  • MODEL

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