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Title: Origin of stretched-exponential photoluminescence relaxation in size-separated silicon nanocrystals

A detailed understanding of the photoluminescence (PL) from silicon nanocrystals (SiNCs) is convoluted by the complexity of the decay mechanism, including a stretched-exponential relaxation and the presence of both nanosecond and microsecond time scales. In this publication, we analyze the microsecond PL decay of size-resolved SiNC fractions in both full-spectrum (FS) and spectrally resolved (SR) configurations, where the stretching exponent and lifetime are used to deduce a probability distribution function (PDF) of decay rates. For the PL decay measured at peak emission, we find a systematic shift and narrowing of the PDF in comparison to the FS measurements. In a similar fashion, we resolve the PL lifetime of the ‘blue’, ‘peak’, and ‘red’ regions of the spectrum and map PL decays of different photon energy onto their corresponding location in the PDF. Furthermore, a general trend is observed where higher and lower photon energies are correlated with shorter and longer lifetimes, respectively, which we relate to the PL line width and electron-phonon coupling.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1]
  1. North Dakota State Univ., Fargo, ND (United States)
  2. North Dakota State Univ., Fargo, ND (United States); Government College for Women, Kerala (India)
Publication Date:
Grant/Contract Number:
FG36-08GO88160
Type:
Published Article
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Journal ID: ISSN 2158-3226
Publisher:
American Institute of Physics (AIP)
Research Org:
North Dakota State Univ., Fargo, ND (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Photoluminescence; Nanocrystals; Solvents; Silicon; Surface oxidation
OSTI Identifier:
1361919
Alternate Identifier(s):
OSTI ID: 1393532; OSTI ID: 1421280