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Title: Can Tauc plot extrapolation be used for direct-band-gap semiconductor nanocrystals?

Despite that Tauc plot extrapolation has been widely adopted for extracting bandgap energies of semiconductors, there is a lack of theoretical support for applying it to nanocrystals. In this paper, direct-allowed optical transitions in semiconductor nanocrystals have been formulated based on a purely theoretical approach. This result reveals a size-dependant transition of the power factor used in Tauc plot, increasing from one half used in the 3D bulk case to one in the 0D case. This size-dependant intermediate value of power factor allows a better extrapolation of measured absorption data. Being a material characterization technique, the generalized Tauc extrapolation gives a more reasonable and accurate acquisition of the intrinsic bandgap, while the unjustified purpose of extrapolating any elevated bandgap caused by quantum confinement is shown to be incorrect.
Authors:
; ; ; ;  [1]
  1. School of Photovoltaic and Renewable Energy Engineering, UNSW Australia, Sydney, NSW 2052 (Australia)
Publication Date:
OSTI Identifier:
22399359
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 77 NANOSCIENCE AND NANOTECHNOLOGY; ABSORPTION; CRYSTALS; ELECTRONIC STRUCTURE; ENERGY GAP; EXTRAPOLATION; NANOSTRUCTURES; POWER FACTOR; SEMICONDUCTOR MATERIALS