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Title: Density functional calculation of the structural and electronic properties of germanium quantum dots

We apply first principles density functional computational methods to study the structures, densities of states (DOS), and higher occupied molecular orbital (HOMO) – lowest unoccupied molecular orbital (LUMO) gaps of selected free-standing Ge semiconductor quantum dots up to 1.8nm. Our calculations are performed using numerical atomic orbital approach where linear combination of atomic orbital was applied. The surfaces of the quantum dots was passivized by hydrogen atoms. We find that surface passivation does affect the electronic properties associated with the changes of surface state, electron localization, and the energy gaps of germanium nanocrystals as well as the confinement of electrons inside the quantum dots (QDs). Our study shows that the energy gaps of germanium quantum dots decreases with the increasing dot diameter. The size-dependent variations of the computed HOMO-LUMO gaps in our quantum dots model were found to be consistent with the effects of quantum confinement reported in others theoretical and experimental calculation.
Authors:
;  [1]
  1. School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi (Malaysia)
Publication Date:
OSTI Identifier:
22391547
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1657; Journal Issue: 1; Conference: PERFIK 2014: National Physics Conference 2014, Kuala Lumpur (Malaysia), 18-19 Nov 2014; 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; CONFINEMENT; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; ELECTRONIC STRUCTURE; ELECTRONS; ENERGY GAP; GERMANIUM; HYDROGEN; MOLECULAR ORBITAL METHOD; PASSIVATION; QUANTUM DOTS; SEMICONDUCTOR MATERIALS; SURFACES