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Title: Optical properties of colloidal germanium nanocrystals

Abstract

Highly crystalline germanium (Ge) nanocrystals in the size range 2--10 nm were grown in inverse micelles and purified and size-separated by high pressure liquid chromatography with on-line optical and electrical diagnostics. The nanocrystals retain the diamond structure of bulk Ge down to at least 2.0 nm (containing about 150 Ge atoms). The background- and impurity-free extinction and photoluminescence (PL) spectra of these nanocrystals revealed rich structure which was interpreted in terms of the bandstructure of Ge shifted to higher energies by quantum confinement. The shifts ranged from {minus}0.1 eV to over 1 eV for the various transitions. PL in the range 350--700 nm was observed from nanocrystals 2--5 nm in size. The 2.0 nm nanocrystals yielded the most intense PL (at 420 nm) which is believed to be intrinsic and attributed to direct recombination at {Gamma}. Excitation at high energy (250 nm) populates most of the conduction bands resulting in competing recombination channels and the observed broad PL spectra.

Authors:
; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
755587
Report Number(s):
SAND2000-1099J
TRN: AH200021%%35
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Journal Name:
Physical Review BIS
Additional Journal Information:
Other Information: Submitted to Physical Review BIS; PBD: 1 May 2000
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; GERMANIUM; OPTICAL PROPERTIES; CRYSTAL STRUCTURE; PHOTOLUMINESCENCE; RECOMBINATION

Citation Formats

WILCOXON,JESS P., PROVENCIO,PAULA P., and SAMARA,GEORGE A. Optical properties of colloidal germanium nanocrystals. United States: N. p., 2000. Web.
WILCOXON,JESS P., PROVENCIO,PAULA P., & SAMARA,GEORGE A. Optical properties of colloidal germanium nanocrystals. United States.
WILCOXON,JESS P., PROVENCIO,PAULA P., and SAMARA,GEORGE A. Mon . "Optical properties of colloidal germanium nanocrystals". United States. https://www.osti.gov/servlets/purl/755587.
@article{osti_755587,
title = {Optical properties of colloidal germanium nanocrystals},
author = {WILCOXON,JESS P. and PROVENCIO,PAULA P. and SAMARA,GEORGE A.},
abstractNote = {Highly crystalline germanium (Ge) nanocrystals in the size range 2--10 nm were grown in inverse micelles and purified and size-separated by high pressure liquid chromatography with on-line optical and electrical diagnostics. The nanocrystals retain the diamond structure of bulk Ge down to at least 2.0 nm (containing about 150 Ge atoms). The background- and impurity-free extinction and photoluminescence (PL) spectra of these nanocrystals revealed rich structure which was interpreted in terms of the bandstructure of Ge shifted to higher energies by quantum confinement. The shifts ranged from {minus}0.1 eV to over 1 eV for the various transitions. PL in the range 350--700 nm was observed from nanocrystals 2--5 nm in size. The 2.0 nm nanocrystals yielded the most intense PL (at 420 nm) which is believed to be intrinsic and attributed to direct recombination at {Gamma}. Excitation at high energy (250 nm) populates most of the conduction bands resulting in competing recombination channels and the observed broad PL spectra.},
doi = {},
journal = {Physical Review BIS},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {5}
}