title: Rate-limiting mechanisms in high-temperature growth of catalyst-free InAs nanowires with large thermal stability.
abstract: We identify the entire growth parameter space and rate-limiting mechanisms in non-catalytic InAs nanowires (NWs) grown by molecular beam epitaxy. Surprisingly huge growth temperature ranges are found with maximum temperatures close to ~600°C upon dramatic increase of V/III ratio, exceeding by far the typical growth temperature range for catalyst-assisted InAs NWs. Based on quantitative in situ line-of-sight quadrupole mass spectrometry, we determine the rate-limiting factors in high-temperature InAs NW growth by directly monitoring the critical desorption and thermal decomposition processes of InAs NWs. Both under dynamic (growth) and static (no growth, ultra-high vacuum) conditions the (111)-oriented InAs NWs evidence excellent thermal stability at elevated temperatures even under negligible supersaturation. The rate-limiting factor for InAs NW growth is hence dominated by In desorption from the substrate surface. Closer investigation of the group-III and group-V flux dependences on growth rate reveals two apparent growth regimes, an As-rich and an In-rich regime defined by the effective As/In flux ratio, and maximum achievable growth rates of > 6 µm h(-1). The unique features of high-T growth and excellent thermal stability provide the opportunity for operation of InAs-based NW materials under caustic environment and further allow access to temperature regimes suitable for alloying non-catalytic InAs NWs with GaAs.
authors.affiliation: Walter Schottky Institut, Physik Department, and Center of Nanotechnology and Nanomaterials, Technische Universität München, Garching, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Hertenberger
authors.forename: D
authors.initials: D
authors.lastname: Rudolph
authors.forename: J
authors.initials: J
authors.lastname: Becker
authors.forename: M
authors.initials: M
authors.lastname: Bichler
authors.forename: J J
authors.initials: JJ
authors.lastname: Finley
authors.forename: G
authors.initials: G
authors.lastname: Abstreiter
authors.forename: G
authors.initials: G
authors.lastname: Koblmüller
mesh_terms: D001152:Arsenicals / Q000737:chemistry*; D002384:Catalysis; D003460:Crystallization / Q000379:methods*; D006358:Hot Temperature; D007204:Indium / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D001152:Arsenicals; D046911:Macromolecular Substances; D007204:Indium; C009495:titanium dioxide; D014025:Titanium; C076773:indium arsenide