Impact of GaAsN capping on strain and quantum confinement in vertically coupled InAs/GaAs quantum dots

Raveesh Gourishetty; Subhananda Chakrabarti

doi:10.1117/12.2594531

1 August 2021 Impact of GaAsN capping on strain and quantum confinement in vertically coupled InAs/GaAs quantum dots

Raveesh Gourishetty, Subhananda Chakrabarti

Proceedings Volume 11800, Low-Dimensional Materials and Devices 2021; 1180018 (2021) https://doi.org/10.1117/12.2594531
Event: SPIE Nanoscience + Engineering, 2021, San Diego, California, United States

Conference Poster

Abstract

The usage of the capping layer on InAs/GaAs quantum dots (QDs) to improve the optical and structural characteristics has been a common practice for decades. Especially in vertically coupled QD structures, the strain plays a significant role in determining the size and shape of the QDs. In this study, we have used GaAsN capping layer with 0% (Sample N1), 0.1% (Sample N2), 1.2% (Sample N3) and 1.8% (Sample N4) Nitride composition to analyze its effects on the emission wavelength, band structure, and the strain build-up in a ten-layer InAs/GaAs Stranksi-Krastanov (SK) QDs that are electronically coupled to six stack submonolayer (SML) QDs. Research revealed that GaAsN capping enables the growth of coupled QDs with high quality and uniformity. GaAsN capping allowed a redshift in the PL emission wavelength with 1072 nm, 1090 nm, 1129 nm, and 1184 nm for samples N1, N2, N3, and N4, respectively. In a self-assembled QD system, the relief in strain is often attributed to the redshift in the emission wavelength. However, the obtained hydrostatic compressive strain indicates that the strain for all these samples N1 to N4 inside the SK QD remains the same. In lieu, we conclude that the redshift in the PL emission wavelength is due to the reduction in the conduction band energy level in the GaAsN capping layer with respect to the GaAs layer that reduces the electron confinement in QDs. The GaAsN capping offering a strong red shift of 1184 nm with minimum strain for coupled QD system can further be used in optoelectronic device studies.

Conference Presentation

Citation Download Citation

Raveesh Gourishetty and Subhananda Chakrabarti "Impact of GaAsN capping on strain and quantum confinement in vertically coupled InAs/GaAs quantum dots", Proc. SPIE 11800, Low-Dimensional Materials and Devices 2021, 1180018 (1 August 2021); https://doi.org/10.1117/12.2594531

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