Investigation on Sb distribution for InSb/InAs sub-monolayer heterostructure using TEM techniques

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Sub-monolayer (SML) InSb/InAs nanostructures offer advantages over Stranski-Krastanov counterparts.
• These include sharper emission spectra, enhanced modal gain, and larger modulation bandwidth.

Purpose of the Study:

• To analyze the antimony (Sb) distribution in SML InSb layers grown by migration-enhanced epitaxy.
• To understand the segregation behavior of Sb during the growth of InSb/InAs nanostructures.

Main Methods:

• Transmission electron microscopy (TEM) techniques were employed.
• Analysis included 002 dark field imaging and atomic column-resolved high-angle annular dark-field scanning TEM (HAADF-STEM).
• The Muraki segregation model was used to quantify Sb segregation.

Main Results:

• A continuous InSbAs layer with low Sb content was observed.
• Scarce Sb-rich InSbAs agglomerates were present.
• A high Sb segregation coefficient (R = 0.81) towards the growth direction was quantified, indicating significant Sb segregation.

Conclusions:

• Sb segregation during the growth of SML InSb/InAs nanostructures is a significant phenomenon.
• The formation of a continuous InSbAs wetting layer is a result of SML Sb deposition on InAs.
• Understanding this segregation is crucial for optimizing SML nanostructure properties.