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Dynamics of mass transport during nanohole drilling by local droplet etching.

Heyn C, Bartsch T, Sanguinetti S, Jesson D, Hansen W - Nanoscale Res Lett (2015)

Bottom Line: This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model.Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material.Furthermore, the depth dependence of the hole side-facet angle is analyzed.

View Article: PubMed Central - PubMed

Affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, Hamburg, 20355 Germany.

ABSTRACT
Local droplet etching (LDE) utilizes metal droplets during molecular beam epitaxy for the self-assembled drilling of nanoholes into III/V semiconductor surfaces. An essential process during LDE is the removal of the deposited droplet material from its initial position during post-growth annealing. This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model. The first set of experiments demonstrates that the droplet material is removed by detachment of atoms and spreading over the substrate surface. Further experiments establish that droplet etching requires a small arsenic background pressure to inhibit re-attachment of the detached atoms. Surfaces processed under completely minimized As pressure show no hole formation but instead a conservation of the initial droplets. Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material. Furthermore, the depth dependence of the hole side-facet angle is analyzed.

No MeSH data available.


Related in: MedlinePlus

Example for the transformation of as-grown droplets into nanoholes with walls during post-growth annealing. (a) AFM micrograph of a GaAs surface with droplets after deposition of 2.0 ML of Ga at T=650°C without annealing together with a perspective view and linescans of a single droplet. (b) GaAs surface with nanoholes after Ga droplet deposition and 120-s annealing.
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Fig1: Example for the transformation of as-grown droplets into nanoholes with walls during post-growth annealing. (a) AFM micrograph of a GaAs surface with droplets after deposition of 2.0 ML of Ga at T=650°C without annealing together with a perspective view and linescans of a single droplet. (b) GaAs surface with nanoholes after Ga droplet deposition and 120-s annealing.

Mentions: After deposition, the material localized in the droplets is functionalized for nanostructure creation. In the most widely used approach, group III metal droplets are crystallized under a group V atmosphere to form III/V semiconductor quantum dots [6-10], quantum dot molecules [12], or quantum ring complexes [13-17]. An alternative approach using a low group V flux is the local droplet etching (LDE), where group III metal droplets drill nanoholes into III/V-semiconductor surfaces [18-25]. An example for a surface with nanoholes after droplet etching is shown in Figure 1b.Figure 1


Dynamics of mass transport during nanohole drilling by local droplet etching.

Heyn C, Bartsch T, Sanguinetti S, Jesson D, Hansen W - Nanoscale Res Lett (2015)

Example for the transformation of as-grown droplets into nanoholes with walls during post-growth annealing. (a) AFM micrograph of a GaAs surface with droplets after deposition of 2.0 ML of Ga at T=650°C without annealing together with a perspective view and linescans of a single droplet. (b) GaAs surface with nanoholes after Ga droplet deposition and 120-s annealing.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385027&req=5

Fig1: Example for the transformation of as-grown droplets into nanoholes with walls during post-growth annealing. (a) AFM micrograph of a GaAs surface with droplets after deposition of 2.0 ML of Ga at T=650°C without annealing together with a perspective view and linescans of a single droplet. (b) GaAs surface with nanoholes after Ga droplet deposition and 120-s annealing.
Mentions: After deposition, the material localized in the droplets is functionalized for nanostructure creation. In the most widely used approach, group III metal droplets are crystallized under a group V atmosphere to form III/V semiconductor quantum dots [6-10], quantum dot molecules [12], or quantum ring complexes [13-17]. An alternative approach using a low group V flux is the local droplet etching (LDE), where group III metal droplets drill nanoholes into III/V-semiconductor surfaces [18-25]. An example for a surface with nanoholes after droplet etching is shown in Figure 1b.Figure 1

Bottom Line: This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model.Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material.Furthermore, the depth dependence of the hole side-facet angle is analyzed.

View Article: PubMed Central - PubMed

Affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, Hamburg, 20355 Germany.

ABSTRACT
Local droplet etching (LDE) utilizes metal droplets during molecular beam epitaxy for the self-assembled drilling of nanoholes into III/V semiconductor surfaces. An essential process during LDE is the removal of the deposited droplet material from its initial position during post-growth annealing. This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model. The first set of experiments demonstrates that the droplet material is removed by detachment of atoms and spreading over the substrate surface. Further experiments establish that droplet etching requires a small arsenic background pressure to inhibit re-attachment of the detached atoms. Surfaces processed under completely minimized As pressure show no hole formation but instead a conservation of the initial droplets. Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material. Furthermore, the depth dependence of the hole side-facet angle is analyzed.

No MeSH data available.


Related in: MedlinePlus