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Title: Significant mobility enhancement in extremely thin highly doped ZnO films

Highly Ga-doped ZnO (GZO) films of thicknesses d = 5, 25, 50, and 300 nm, grown on 160-nm ZnO buffer layers by molecular beam epitaxy, had 294-K Hall-effect mobilities μ{sub H} of 64.1, 43.4, 37.0, and 34.2 cm{sup 2}/V-s, respectively. This extremely unusual ordering of μ{sub H} vs d is explained by the existence of a very high-mobility Debye tail in the ZnO, arising from the large Fermi-level mismatch between the GZO and the ZnO. Scattering theory in conjunction with Poisson analysis predicts a Debye-tail mobility of 206 cm{sup 2}/V-s at the interface (z = d), falling to 58 cm{sup 2}/V-s at z = d + 2 nm. Excellent fits to μ{sub H} vs d and sheet concentration n{sub s} vs d are obtained with no adjustable parameters.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ; ;  [4]
  1. Semiconductor Research Center, Wright State University, 3640 Colonel Glenn Hwy., Dayton, Ohio 45435 (United States)
  2. (United States)
  3. Air Force Research Laboratory Materials and Manufacturing Directorate, 3005 Hobson Way, Wright-Patterson AFB, Ohio 45433 (United States)
  4. Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan (China)
Publication Date:
OSTI Identifier:
22398896
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 15; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BUFFERS; CARRIER MOBILITY; CONCENTRATION RATIO; DEBYE LENGTH; DOPED MATERIALS; FERMI LEVEL; GALLIUM COMPOUNDS; HALL EFFECT; INTERFACES; LAYERS; MOBILITY; MOLECULAR BEAM EPITAXY; SCATTERING; THIN FILMS; ZINC OXIDES