Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microsc...

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Bibliographic Details
Main Authors: Rajeev R. Kosireddy, Stephen T. Schaefer, Marko S. Milosavljevic, Shane R. Johnson
Format: Article
Language:English
Published: MDPI AG 2021-06-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/8/6/215
Description
Summary:Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>[</mo><mrow><mn>01</mn><mover accent="true"><mn>1</mn><mo>¯</mo></mover></mrow><mo>]</mo></mrow></mrow></semantics></math></inline-formula> step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.
ISSN:2304-6732