Droplet epitaxy of InAs nanocrystals on GaN/GaAs

Citation
I. Pietzonka et al., Droplet epitaxy of InAs nanocrystals on GaN/GaAs, JPN J A P 1, 40(11), 2001, pp. 6531-6535
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Volume
40
Issue
11
Year of publication
2001
Pages
6531 - 6535
Database
ISI
SICI code
0021-4922(200111)40:11<6531:DEOINO>2.0.ZU;2-2
Abstract
The growth of InAs nanocrystals fabricated on GaAs by means of droplet epit axy in a metal-organic chemical vapour-deposition chamber was investigated. To prevent deterioration of the droplet/substrate interface a nitride pass ivation layer was introduced. For this purpose both, nitridation of GaAs an d GaN growth at different temperatures have been applied. In all nitrided s amples and when GaN was grown at T-g = 450 degreesC, deep pit-like defects have been found in the GaAs below the InAs islands, caused by In that diffu sed from the droplets into the substrate along the {111} planes. Only the g rowth of a thin cubic GaN layer at T-g = 550 degreesC effectively prevented this indiffusion of indium into the substrate. The InAs islands contained stacking faults and twins that arose from defects in the underlying GaN lay er. Their sidewalls do not only consist of (001) and {111} facets, but also of the commonly not observed {110} and even {11 (1) over bar} facets. The frequent occurrence of holes at the center base of the InAs islands is disc ussed within a growth model for the transformation of In droplets to InAs n anocrystals.