STUDIES FROM YEREVAN STATE UNIVERSITY UPDATE CURRENT DATA ON QUANTUM DOTS
Nanotechnology Business Journal
May 10, 2010
"An example of InAsSbP quaternary quantum dots (QDs), pits and
dots-pits cooperative structures’ growth on InAs(100) substrates by
liquid phase epitaxy (LPE) is reported. The interaction and surface
morphology of the dots-pits combinations are investigated by the
high-resolution scanning electron microscope," scientists in Yerevan,
Armenia report.
"Bimodal growth mechanism for the both QDs and pits nucleation is
observed. Cooperative structures consist of the QDs banded by pits,
as well as the "large" pits banded by the quantum wires are detected.
The composition of the islands and the pits edges is found to be
quaternary, enriched by antimony and phosphorus, respectively. This
repartition is caused by dissociation of the wetting layer, followed
by migration (surface diffusion) of the Sb and P atoms in opposite
directions. The "small" QDs average density ranges from 0.8 to 2 x
10(9) cm(-2), with heights and widths dimensions from 2 to 20 nm and
5 to 45 nm, respectively. The average density of the "small" pits is
equal to (6-10) x 10(9) cm(-2) with dimensions of 5-40 nm in width and
depth. Lifshits-Slezov-like distribution for the amount and surface
density of both "small" QDs and pits versus their average diameter
is experimentally detected," wrote K.M. Gambaryan and colleagues,
Yerevan State University.
The researchers concluded: "A displacement of the absorption edge
toward the long wavelength region and enlargement toward the short
wavelength region is detected by the Fourier transform infrared
spectrometry."
Gambaryan and colleagues published their study in Nanoscale Research
Letters (Interaction and Cooperative Nucleation of InAsSbP Quantum
Dots and Pits on InAs(100) Substrate. Nanoscale Research Letters,
2010;5(3):587-591).
For more information, contact K.M. Gambaryan, Yerevan State University,
Dept. of Physics Semicond & Microelect, 1 A Manoukian Str, Yerevan
0025, Armenia.
Publisher contact information for the journal Nanoscale Research
Letters is: Springer, 233 Spring St., New York, NY 10013, USA.