Growth of 6.2 Å semiconductor topological materials on lattice engineered virtual substrates

H. J. Haugan; A. M. Hilton; K. Mahalingam; A. T. Neal; S. Elhamri; R. G. Bedford; K. G. Eyink

doi:10.1117/12.2675731

10 October 2023 Growth of 6.2 Å semiconductor topological materials on lattice engineered virtual substrates

H. J. Haugan, A. M. Hilton, K. Mahalingam, A. T. Neal, S. Elhamri, R. G. Bedford, K. G. Eyink

Proceedings Volume 12687, Infrared Sensors, Devices, and Applications XIII; 126870G (2023) https://doi.org/10.1117/12.2675731
Event: SPIE Optical Engineering + Applications, 2023, San Diego, California, United States

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Abstract

To test whether conventional infrared materials can be used to control the electronic wavefunction to form a topological state, a 6.2 Å metamorphic (InAs/InGaSb/InAs) quantum well (QW) absorber with ~60 meV of hybridization gap (Δ) was investigated. We developed a thick metamorphic InGaSb buffer layer on GaAs wafer to create a 6.2 Å lattice constant for the QW growths. The lattice constant of virtual substrates (VSs) was very close to the target value of 6.2 Å, however the resulting crystalline quality of the VSs was inefficient for topological insulator. The cross-sectional transmission electron microscopy image revealed that the dislocation density in the InGaSb buffer layer was high closer to the GaAs substrate and gradually reduced upon continued growth. However some mismatch-related defects were propagated into the absorber region, consequently degraded the transport quality of absorber. The QW absorber grown on VS had a low mobility. The mobility was dramatically improved by selecting pseudomorphic QW or superlattice absorber with a small Δ that was grown on a lattice-matched GaSb substrate. Hence, in order for the proposed 6.2 Å materials to be viable for sensing applications, a critical effort will be the development of better optimized metamorphic buffers for the design or of highlyhybridized psedomorphic designs that can be grown on lattice-matched substrates.

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H. J. Haugan, A. M. Hilton, K. Mahalingam, A. T. Neal, S. Elhamri, R. G. Bedford, and K. G. Eyink "Growth of 6.2 Å semiconductor topological materials on lattice engineered virtual substrates", Proc. SPIE 12687, Infrared Sensors, Devices, and Applications XIII, 126870G (10 October 2023); https://doi.org/10.1117/12.2675731

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