Compositional analysis of oxide-embedded III-V nanostructures

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Physics

Background:

• Embedded heterostructures, with one material encased in another, are formed via nanowire growth.
• Materials-selective oxidation allows combining amorphous oxides with crystalline materials like III-V semiconductors.
• Characterizing these structures with transmission electron microscopy (TEM) is difficult due to overlapping materials in projection and electron beam sensitivity.

Purpose of the Study:

• To evaluate two techniques for analyzing embedded materials: local lattice parameter measurements and bulk plasmon energy measurements.
• To assess the performance of these techniques on InP-AlInP segments embedded in amorphous aluminum oxide.
• To investigate the complementarity and limitations of these methods, especially under strain.

Main Methods:

• High-resolution micrographs for local lattice parameter measurements.
• Electron energy loss spectroscopy (EELS) for bulk plasmon energy measurements.
• Molecular dynamics simulations to analyze residual strain.

Main Results:

• Both lattice parameter and plasmon energy measurements successfully analyzed the embedded InP-AlInP segments.
• The two techniques demonstrated excellent agreement in strain-free regions.
• Divergence in results was observed in strained regions, with each technique deviating in opposite directions from the true value.

Conclusions:

• Local lattice parameter and bulk plasmon energy measurements are complementary techniques for characterizing oxide-embedded nanowire heterostructures.
• These methods are effective even at reduced electron doses, addressing a key challenge in TEM analysis.
• Understanding the influence of residual strain is crucial, as it can cause these techniques to yield differing results.