Self-Catalyzed Growth and Characterization of In(As)P Nanowires on InP(111)B Using Metal-Organic Chemical Vapor Deposition

Abstract

We report the growth of vertical <111>-oriented InAsxP1−x (0.11 ≤ x ≤ 0.27) nanowires via metal-organic chemical vapor deposition in the presence of indium droplets as catalysts on InP(111)B substrates at 375 °C. Trimethylindium, tertiarybutylphosphine, and tertiarybutylarsine are used as the precursors, corresponding to P/In and As/In molar ratios of 29 and 0.01, respectively. The as-grown nanowire growth morphologies, crystallinity, composition, and optical characteristics are determined using a combination of scanning and transmission electron microscopies, electron diffraction, and X-ray photoelectron, energy dispersive X-ray, and Raman spectroscopies. We find that the InAsxP1−x nanowires are tapered with narrow tops, wider bases, and In-rich In-As alloy tips, characteristic of vapor-liquid-solid process. The wires exhibit a mixture of zinc blende and wurtzite crystal structures and a high density of structural defects such as stacking faults and twins. Our results suggest that the incorporation of As into InP wires decreases with increasing substrate temperature. The Raman spectra obtained from the In(As)P nanowires reveal a red-shift and lower intensity of longitudinal optical mode relative to both InP nanowires and InP(111)B bulk, due to the incorporation of As into the InP matrix.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1427-4) contains supplementary material, which is available to authorized users.

Raman Spectroscopic Characterizations of Self-Catalyzed InP/InAs/InP One-Dimensional Nanostructures on InP(111)B Substrate using a Simple Substrate-Tilting Method

“…All nanostructures grow vertically and straight in the <111>B direction with slight tapering. The pillars are low profile due to the two competitive growth modes, vapor-liquid-solid and vapor phase epitaxy, that are active at a relatively high growth temperature of 400 °C [13, 41]. The nanopillars are 150 nm in base diameter and up to 250 nm in height while the nanocones are 50 nm in base diameter and up to 2 μm in height.…”

“…2. The Raman intensities of the InAs peaks in InP/InAs/InP nanostructures are lower than those of the InAs(111)B reference, indicating that both nanopillar and nanocones are either core-shell or InPAs alloy structures [13, 42]. Interestingly, the redshifts of InAs E 1 (LO) and InAs A 1 (LO) peaks compared with InAs bulk crystal with significant broadening are found in InP/InAs/InP nanopillars (see Additional file 1: Figure S2).…”

“…However, due to the presence of substrate tilt, additional contribution from the (110) and (100) surface will be added into the TO and LO phonons, respectively. In our previous reports, it was determined that the nanopillars have wurtzite crystal structure oriented parallel to the [0001] axis [42] but the nanocones have zinc blende crystal structure with [111] normal to the substrate [13, 55]. The set of {1–100} planes are the side facets of the nanopillars.…”

“…One-dimensional nanostructures (nanopillars and nanocones) were grown via self-catalyzed vapor-liquid-solid process on InP(111)B substrate by a Veeco D125 MOVPE reactor using trimethylindium (TMIn), tertiarybutylphosphine (TBP), and tertiarybutylarsine (TBA) as precursors [13, 23, 41]. Nanopillars and nanocones were grown at substrate temperatures of ~ 350 °C and ~ 400 °C, respectively.…”

“…A variety of material combinations have been synthesized both in core-shell [2–5] and superlattice [6–8] and alloy nanowires [9, 10]. InP-InAs nanowire [11–13] is one of such combinations with potential applications in light-emitting diodes [14], single-photon source [15], photodetectors [16], and heterojunction transistors [17] due to its band gap tunability, high carrier mobility, and large breakdown field [18, 19]. The performance of any of these devices depends on the optical and electronic properties of nanoscale semiconductors, which in turn vary critically with the crystallinity, morphology, and composition of the nanowires [20, 21].…”