Morphology and valence band offset of GaSb quantum dots grown on GaP(001) and their evolution upon capping

Desplanque, L.; Coinon, C.; Tománek, David; Ruterana, P.; Patriarche, G.; Bonato, Leo; Bimberg, D.; Wallart, X.

doi:10.1088/1361-6528/aa6f41

Cited by 9 publications

(9 citation statements)

References 37 publications

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“…The IFIGS‐and‐electronegativity concept is to date considered a good method for providing such an estimate. Indeed, this theory has recently been well confirmed for the material system GaSb/GaP, where the predicted VBO of 0.67 eV agrees very well with the measured value of 0.65 eV between GaSb QDs and GaP matrix . For the two QD‐systems In 0.5 Ga 0.5 As/GaP and In 0.5 Ga 0.5 Sb/GaP it yields values for VBOs of ≈0.3 and ≈0.6 eV, respectively, and therefore the measured value of E loc = 0.370 (±0.008) eV is within the predicted limit.…”

Section: Electrical Characterizationsupporting

confidence: 78%

MOVPE‐Growth of InGaSb/AlP/GaP(001) Quantum Dots for Nanoscale Memory Applications

Sala

Arikan

Bonato

et al. 2018

Physica Status Solidi (b)

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The structural and optical properties of InGaSb/GaP(001) type‐II quantum dots (QDs) grown by metalorganic vapor phase epitaxy (MOVPE) are studied. Growth strategies as growth interruption (GRI) after deposition of InGaSb and Sb‐flush prior to QD growth are used to tune the structural and optical properties of InGaSb QDs. The Sb‐flush affects the surface diffusion leading to more homogeneous QDs and to a reduction of defects. A ripening process during GRI occurs, where QD size is increased and QD‐luminescence remarkably improved. InGaSb QDs are embedded in GaP n + p‐diodes, employing an additional AlP barrier, and characterized electrically. A localization energy of 1.15 eV for holes in QDs is measured by using deep‐level transient spectroscopy (DLTS). The use of Sb in QD growth is found to decrease the associated QD capture cross‐section by one order of magnitude with respect to the one of In0.5Ga0.5As/GaP QDs. This leads to a hole storage time of almost 1 h at room temperature, which represents to date the record value for MOVPE‐grown QDs, making MOVPE of InGaSb/GaP related QDs a promising technology for QD‐based nano‐memories.

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Section: Electrical Characterizationsupporting

confidence: 78%

MOVPE‐Growth of InGaSb/AlP/GaP(001) Quantum Dots for Nanoscale Memory Applications

Sala

Arikan

Bonato

et al. 2018

Physica Status Solidi (b)

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“…These Sb atoms were not incorporated during the QD growth and segregated into the capping layer. The mechanism of Sb segregation into the capping layer is well known, and it has been also observed for GaSb/GaP QDs grown by MBE 84 . A similar concentration of In atoms is identified in the capping layer, segregated from QDs.…”

Section: Resultsmentioning

confidence: 83%

Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots

et al. 2021

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We investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots (QDs) with potential applications in QD-Flash memories by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). The combination of X-STM and APT is a very powerful approach to study semiconductor heterostructures with atomic resolution, which provides detailed structural and compositional information on the system. The rather small QDs are found to be of truncated pyramid shape with a very small top facet and occur in our sample with a very high density of ∼4 × 1011 cm−2. APT experiments revealed that the QDs are GaAs rich with smaller amounts of In and Sb. Finite element (FE) simulations are performed using structural data from X-STM to calculate the lattice constant and the outward relaxation of the cleaved surface. The composition of the QDs is estimated by combining the results from X-STM and the FE simulations, yielding ∼InxGa1 − xAs1 − ySby, where x = 0.25–0.30 and y = 0.10–0.15. Noticeably, the reported composition is in good agreement with the experimental results obtained by APT, previous optical, electrical, and theoretical analysis carried out on this material system. This confirms that the InGaSb and GaAs layers involved in the QD formation have strongly intermixed. A detailed analysis of the QD capping layer shows the segregation of Sb and In from the QD layer, where both APT and X-STM show that the Sb mainly resides outside the QDs proving that Sb has mainly acted as a surfactant during the dot formation. Our structural and compositional analysis provides a valuable insight into this novel QD system and a path for further growth optimization to improve the storage time of the QD-Flash memory devices.

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“…Such Sb concentration increase in QDs increases the carrier confinement and will subsequently lead to an increase of the QD storage time, which is of utmost importance for the implementation of such QDs into nano-memory devices [23,76]. However, the use of Sb, and its potential partial segregation [37,77], may lead to the formation of additional point defects, which could affect the storage time by increasing capture cross-section [78]. Therefore, the development of the truly defect-free Sb-rich QDs on top of GaP is the key for further improvement of QD-Flash nano-memories.…”

Section: Discussionmentioning

confidence: 99%

On the importance of antimony for temporal evolution of emission from self-assembled (InGa)(AsSb)/GaAs quantum dots on GaP(001)

Steindl,

Sala,

Alén

et al. 2021

Preprint

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Understanding the carrier dynamics of nanostructures is the key for development and optimization of novel semiconductor nano-devices. Here, we study the optical properties and carrier dynamics of (InGa)(AsSb)/GaAs/GaP quantum dots (QDs) by means of non-resonant energy and temperature modulated time-resolved photoluminescence. Studying this material system is important in view of the ongoing implementation of such QDs for nano memory devices. Our set of structures contains a single QD layer, QDs overgrown by a GaSb capping layer, and solely a GaAs quantum well, respectively. Theoretical analytical models allow us to discern the common spectral features around the emission energy of 1.8 eV related to GaAs quantum well and GaP substrate. We observe type-I emission from QDs with recombination times between 2 ns and 10 ns, increasing towards lower energies. The distribution suggests the coexistence of momentum direct and indirect QD transitions. Moreover, based on the considerable tunability of the dots depending on Sb incorporation, we suggest their utilization as quantum photonic sources embedded in complementary metal-oxide-semiconductor (CMOS) platforms, since GaP is almost lattice-matched to Si. Finally, our analysis confirms the nature of the pumping power blue-shift of emission originating from the charged-background induced changes of the wavefunction topology.

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Morphology and valence band offset of GaSb quantum dots grown on GaP(001) and their evolution upon capping

Cited by 9 publications

References 37 publications

MOVPE‐Growth of InGaSb/AlP/GaP(001) Quantum Dots for Nanoscale Memory Applications

MOVPE‐Growth of InGaSb/AlP/GaP(001) Quantum Dots for Nanoscale Memory Applications

Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski–Krastanov quantum dots

On the importance of antimony for temporal evolution of emission from self-assembled (InGa)(AsSb)/GaAs quantum dots on GaP(001)

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