skip to main content

Title: Metal-insulator transitions in IZO, IGZO, and ITZO films

In this study, we measured the low-temperature resistivity of amorphous two- and three-dimensional (2D and 3D) indium-zinc oxide, indium-gallium-zinc oxide, and indium-tin-zinc oxide films with a wide range of carrier densities. To determine their critical characteristics at the metal-insulator transition (MIT), we used the Ioffe–Regel criterion. We found that the MIT occurs in a narrow range between k{sub F}ℓ =0.13 and k{sub F}ℓ =0.25, where k{sub F} and ℓ are the Fermi wave number and electron mean free path, respectively. For films in the insulating region, we analyzed ρ(T) using a procedure proposed by Zabrodskii and Zinov'eva. This analysis confirmed the occurrence of Mott and Efros–Shklovskii (ES) variable-range hopping. The materials studied show crossover behavior from exp(T{sub Mott}/T){sup 1/4} or exp(T{sub Mott}/T){sup 1/3} for Mott hopping conduction to exp(T{sub ES}/T){sup 1/2} for ES hopping conduction with decreasing temperature. For both 2D and 3D materials, we found that the relationship between T{sub Mott} and T{sub ES} satisfies T{sub ES}∝T{sub Mott}{sup 2/3}.
Authors:
 [1] ; ; ; ;  [2] ; ; ;  [3]
  1. National Institute of Information and Communications Technology, Kobe 651-2492 (Japan)
  2. Department of Physics, Kyushu University, Fukuoka 810-8560 (Japan)
  3. Central Research Laboratories, Idemitsu Kosan Co. Ltd, Chiba 299-0293 (Japan)
Publication Date:
OSTI Identifier:
22305823
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMORPHOUS STATE; CARRIER DENSITY; ELECTRIC CONDUCTIVITY; ELECTRONS; FILMS; GALLIUM OXIDES; INDIUM OXIDES; MEAN FREE PATH; PHASE TRANSFORMATIONS; TIN OXIDES; ZINC OXIDES