Vertical carrier transport in strain-balanced InAs/InAsSb type-II superlattice material

Lilian K. Casias, Christian P. Morath, Elizabeth H. Steenbergen, Gilberto A. Umana-Membreno, Preston T. Webster, Julie V. Logan, Jin K. Kim, Ganesh Balakrishnan, Lorenzo Faraone, Sanjay Krishna

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16 Citations (Scopus)


Anisotropic carrier transport properties of unintentionally doped InAs/InAs0.65Sb0.35 type-II strain-balanced superlattice material are evaluated using temperature-and field-dependent magnetotransport measurements performed in the vertical direction on a substrate-removed metal-semiconductor-metal device structure. To best isolate the measured transport to the superlattice, device fabrication entails flip-chip bonding and backside device processing to remove the substrate material and deposit contact metal directly to the bottom of an etched mesa. High-resolution mobility spectrum analysis is used to calculate the conductance contribution and corrected mixed vertical-lateral mobility of the two carrier species present. Combining the latter with lateral mobility results from in-plane magnetotransport measurements on identical superlattice material allows for the calculation of the true vertical majority electron and minority hole mobilities; amplitudes of 4.7 × 10 3 cm2/V s and 1.60 cm2/V s are determined at 77 K, respectively. The temperature-dependent results show that vertical hole mobility rapidly decreases with decreasing temperature due to trap-induced localization and then hopping transport, whereas vertical electron mobility appears phonon scattering-limited at high temperature, giving way to interface roughness scattering at low temperatures, analogous to the lateral electron mobility but with a lower overall magnitude.

Original languageEnglish
Article number182109
JournalApplied Physics Letters
Issue number18
Publication statusPublished - 4 May 2020


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