Tuning the Au‐Free InSb Nanocrystal Morphologies Grown by Patterned Metal–Organic Chemical Vapor Deposition

Abstract

4311www.MaterialsViews.com wileyonlinelibrary.com quantum physical phenomena and spinorbit systems. [18][19][20] Despite these attractive properties, advanced development in InSb-based technology has been diffi cult because of a lack of semi-insulating, lattice-matched substrates, and convoluted epitaxial constraints. Recent progress in nano-heteroepitaxy, however, has enabled high-quality III-V NPs to form on highly lattice-mismatched substrates. [ 3,21 ] This advancement opens the door for heterogeneous integration of high-performance InSb NP devices on cheaper and more readily available platforms.Exploration of InSb in the NP community is a growing research interest, with the fi rst reports appearing in 2005. InSb NPs have been grown using Au-assisted chemical beam epitaxy, [ 22,23 ] Au-catalyzed metal-organic chemical vapor deposition (MOCVD), [24][25][26] thermal CVD, [ 27 ] electrodeposition in porous templates, [ 28 ] and self-nucleation. [ 29 ] Almost all recently published methods are based on epitaxial techniques that generally use Au catalysts and an initial formation of InAs NP segments to assist the InSb NP formation. However, there has been evidence of Au atom contamination in the NPs using Au-catalyzed growth [ 30 ] ; Au is known to create recombination centers in III-V semiconductors. This can signifi cantly reduce the minority carrier lifetime and increase scattering, therefore hampering the device performance. Moreover, the necessity of using short InAs segments to assist InSb NP formation can further complicate practical device fabrication because of the large band-offset and type-III, broken-gap band alignment between InAs and InSb. [ 31 ] In this work, we provide a thorough study of direct InSb nanostructure formation on patterned InAs (111)B substrates, by MOCVD, without the use of Au catalysts and short InAs segments. We investigate various growth conditions that result in different types of InSb nanostructures, including the conditions required to achieve vertical NP growth. Our observations are then explained by fi rst-principles calculations using density-function theory (DFT). This paper provides a basic ground work for potential optoelectronic and electronic devices based on Au-free InSb NPs. MethodsInSb nanostructures are grown on patterned InAs (111)B substrates with a low-pressure (60 torr) vertical Emcore MOCVD reactor, using trimethylindium (TMIn) and trimethylantimony (TMSb) as precursors. The InAs substrates are patterned with A thorough study of direct InSb nanocrystal formations on patterned InAs (111)B substrates is provided. These nanostructures are created without the use of Au catalysts or initial InAs segments. Under the growth conditions generally used for selective-area, catalyst-free epitaxy, a wide range of InSb nanocrystal morphologies are observed. This is because the low-energy InSb surfaces, studied by fi rst-principles calculations, are the {111} facets as opposed to the {110} facets. By controlling the V/III ratio during growth, different InSb nanostructures can...

Free-Standing Two-Dimensional Single-Crystalline InSb Nanosheets

“…S7 and S8). As observed in InSb nanocrystals grown with a high Sb/In BEP ratio 26 , the side facets with low surface energy such as {111} and {011} can be clearly seen in our InSb nanosheets ( Fig. 2d, Supplementary Fig.…”

Indium Antimonide Nanowires: Synthesis and Properties

“…The amount of precursors transported to the growth surface usually depends upon the cracking probability at the surface of catalyst and source temperature. Synthesis of InSb NWs, must not be but it can be executed at significantly low pressures where highly pure hydrogen gas is used as carrier gas and antioxidant [ 35 , 36 ] with molar fraction of 1.1 × 10 −5 for TMIn and 3.4 × 10 −3 for TMSb [ 37 ]. Growth can be modified by controlling the precursor before depositing on the substrate surface just by regulation of growth temperature.…”

“…Catalyst-free growth, second phenomena for NW growth via tip-led process of individual NW, is necessary for avoiding contaminations in metal-organic chemical vapor depositions [ 24 , 50 , 51 ], where it was observed that NWs can be grown by using antimony cluster as catalyst on their tip. Remarkable about this layer-assisted growth is that the yield of the final amount of InSb NW length as well as diameter is sufficiently high [ 50 ] compared to metal-assisted growth [ 36 ]. For several micrometer-long crystalline InSb NWs with diameters varying from about 300 to 500 nm and 4–5 μm in length, the growth process should be carried out for a longer time which may also increase the diameter of the NWs, enclosed with amorphous coating of precursors up to few 10 nm [ 50 ].…”

Size- and shape-dependent phase diagram of In–Sb nano-alloys

“…The values are taken from nanoparticle and nanowire phase diagrams calculated for InSb{111} and InSb{110} surface energies, respectively (corresponding to solid lines of Fig. been shown that self-seeded InSb nanowires can be grown using either In 7,9,10,44 or Sb seed particles 10 , by keeping In-and Sb-rich conditions during the growth, respectively. been shown that self-seeded InSb nanowires can be grown using either In 7,9,10,44 or Sb seed particles 10 , by keeping In-and Sb-rich conditions during the growth, respectively.…”