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Title: Ni{sub x}Cd{sub 1−x}O: Semiconducting alloys with extreme type III band offsets

We have synthesized alloys of NiO and CdO that exhibit an extreme type III band offset and have studied the structural, electrical, and optical properties of Ni{sub x}Cd{sub 1−x}O over the entire composition range. The alloys are rocksalt structured and exhibit a monotonic shift of the (220) diffraction peak to higher 2θ angles with increasing Ni concentration. The electron mobility and electron concentration decrease with increasing x, and samples become insulating for Ni content x > 0.44. This decrease in n-type conductivity is consistent with the movement of the conduction band minimum from below to above the Fermi stabilization energy with increasing Ni content. The optical absorption edge of the alloys can be tuned continuously from CdO to NiO. The intrinsic gap of the alloys was calculated with the electrical and optical measurements and accounting for Burstein-Moss carrier filling and carrier-induced bandgap renormalization effects. We observe an uncommon composition dependence of the intrinsic bandgap on the alloy composition. The effect is tentatively attributed to an interaction between extended states of the conduction band and localized d-states of Ni.
Authors:
; ;  [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [4] ;  [1]
  1. Lawrence Berkeley National Laboratory, Materials Sciences Division, Berkeley, California 94720 (United States)
  2. (United States)
  3. (China)
  4. (Hong Kong)
Publication Date:
OSTI Identifier:
22399109
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 2; 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; ABSORPTION; CADMIUM OXIDES; CHARGE CARRIERS; CONCENTRATION RATIO; D STATES; DIFFRACTION; ELECTRIC CONDUCTIVITY; ELECTRON MOBILITY; ELECTRONS; NICKEL; NICKEL OXIDES; N-TYPE CONDUCTORS; OPTICAL PROPERTIES; STABILIZATION