Document Detail


Spatial Variation of Available Electronic Excitations Within Individual Quantum Dots.
MedLine Citation:
PMID:  23276278     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Quantum dots (QDs) allow for manipulation of the position and energy levels of electrons at sub-10nm length scales through control of material chemistry, size, and shape. It is known from optical studies that the bandgap of semiconductor QDs increases as their size decreases, due to the narrowing of the quantum confinement potential. The mechanism of quantum confinement also indicates that the localized properties within individual QDs should depend on their shape in addition to their size, but direct observations of this effect have proven challenging due to the limited spatial resolution of measurement techniques at this scale and the ability to remove contributions from the surroundings. Here we present experimental evidence of spatial variations in the lowest available electron energy transition within a series of single electrically isolated QDs due to a dome-shaped geometry, measured using electron energy-loss spectroscopy in a (scanning) transmission electron microscope [(S)TEM-EELS]. We observe a consistent increase in the energy onset of electronic excitations from the lateral center of the dot towards the edges, which we attribute purely to shape. This trend is in qualitative agreement with a simple quantum simulation of the local density of states in a dome-shaped QD.
Authors:
Hee Joon Jung; Neil P Dasgupta; Philip B Van Stockum; Ai Leen Koh; Robert Sinclair; Fritz B Prinz
Related Documents :
23754808 - The inevitable journey to being.
23376268 - Experimental and theoretical investigations of spectroscopic properties of 8-chloro-1-m...
23718568 - Evolution of electric dipole (hyper)polarizabilities of β-strand polyglycine single ch...
24699768 - Coexistence of an anatase/tio2(b) heterojunction and an exposed (001) facet in tio2 nan...
1250708 - Chromatin model calculations: arrays of spherical nu bodies.
18620318 - Ultrastructural changes in the secretion granules of the hypopharyngeal glands of the h...
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-31
Journal Detail:
Title:  Nano letters     Volume:  -     ISSN:  1530-6992     ISO Abbreviation:  Nano Lett.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2013-1-1     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101088070     Medline TA:  Nano Lett     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Prognostic value of B-type natriuretic peptide (BNP) and its potential role in guiding fluid therapy...
Next Document:  An unusual conformation of ?-melanocyte-stimulating hormone analogues leads to a selective human mel...