Merging Nanowires and Formation Dynamics of Bottom‐Up Grown InSb Nanoflakes

Abstract

AbstractIndium Antimonide (InSb) is a semiconductor material with unique properties, that are suitable for studying new quantum phenomena in hybrid semiconductor‐superconductor devices. The realization of such devices with defect‐free InSb thin films is challenging, since InSb has a large lattice mismatch with most common insulating substrates. Here, the controlled synthesis of free‐standing 2D InSb nanostructures, termed as “nanoflakes”, on a highly mismatched substrate is presented. The nanoflakes originate from the merging of pairs of InSb nanowires grown in V‐groove incisions, each from a slanted and opposing {111}B facet. The relative orientation of the two nanowires within a pair, governs the nanoflake morphologies, exhibiting three distinct ones related to different grain boundary arrangements: no boundary (type‐I), Σ3‐ (type‐II), and Σ9‐boundary (type‐III). Low‐temperature transport measurements indicate that type‐III nanoflakes are of a relatively lower quality compared to type‐I and type‐II, based on field‐effect mobility. Moreover, type‐III nanoflakes exhibit a conductance dip attributed to an energy barrier pertaining to the Σ9‐boundary. Type‐I and type‐II nanoflakes exhibit promising transport properties, suitable for quantum devices. This platform hosting nanoflakes next to nanowires and nanowire networks can be used to selectively deposit the superconductor by inter‐shadowing, yielding InSb‐superconductor hybrid devices with minimal post‐fabrication steps.