16 research outputs found
Interaction and Cooperative Nucleation of InAsSbP Quantum Dots and Pits on InAs(100) Substrate
An example of InAsSbP quaternary quantum dots (QDs), pits and dotsâpits cooperative structuresâ growth on InAs(100) substrates by liquid phase epitaxy (LPE) is reported. The interaction and surface morphology of the dotsâpits combinations are investigated by the high-resolution scanning electron microscope. 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 âlargeâ 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 âsmallâ QDs average density ranges from 0.8 to 2 Ă 109 cmâ2, with heights and widths dimensions from 2 to 20 nm and 5 to 45 nm, respectively. The average density of the âsmallâ pits is equal to (6â10) Ă 109 cmâ2 with dimensions of 5â40 nm in width and depth. LifshitsâSlezov-like distribution for the amount and surface density of both âsmallâ QDs and pits versus their average diameter is experimentally detected. 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