What is it about?

Indium arsenide (InAs) nanostructures deposited on gallium arsenide (GaAs) substrates have interesting optoelectronic properties but, this system is also prone to defect formation due to the large lattice mismatch. In this work, we introduce a novel nanopillar patterned GaAs template with pillar tops surrounded by a silicon nitride mask. Such a configuration enables the nanopillar tops to mimic nanoscale growth sites. InAs quantum dots (QDs) deposited by molecular beam epitaxy on such substrates are shown to be defect free under optimized growth conditions. This observation and the efficacy of InAs QD surfaces at relieving lattice strain are corroborated by a detailed electron microscopic investigation.

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Why is it important?

A major outcome of this work is the formation of defect free InAs QDs on the GaAs(111)A substrates. This was hitherto proven unachievable using planar bulk substates of the same orientation. Additionally, the ability to form QDs with such high areal densities predetermined by selective area sites opens avenues for new optoelectronic device applications.


This work demonstrates the ability to nanopattern wafer scale samples employing nanosphere lithography, a cost effective bottom-up method. Furthermore, the developed selective area epitaxy scheme shows potential for transferability to other substrates such as Si(111) and GaAs(111)B. This opens new avenues for site selective growth of axial nanowires which are vital components for building highly efficient optoelectronic devices.

Vinay Kunnathully
Universitat Paderborn

Read the Original

This page is a summary of: Selective area heteroepitaxy of InAs nanostructures on nanopillar-patterned GaAs(111)A, Journal of Applied Physics, November 2022, American Institute of Physics,
DOI: 10.1063/5.0121559.
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