InP NWs Research Articles

Fabrication of InP Vertical Gate-All-Around Transistors Using Crystal Phase Transition Heterojunction

The crystal phase heterojunction (CPHJ) is essentially a new type of heterojunction without misfit dislocations and lattice relaxation. The transistor structure using the CPHJ could significantly impact the transistor technologies. However, CPHJ has difficulty in fabricating a gate structure that modulates the electric field normal to the the CPHJ. Here, we report on the selective-area growth of WZ-InP NWs for InP NWs and demonstration of vertical gate-all-around transistors using the InP CPHJ.

III-V nanowires with quantum dots: MBE growth and properties

We demonstrate growth of AlGaAs NWs with GaAs QDs and InP NWs with InAsP QDs on silicon substrates. Results of GaAs QDs optical properties study have shown that these objects are sources of single photons. In case of InP NWs with InAsP QDs, the results showed that ~ 100% of homogeneously oriented NWs were formed with good optical quality of this system on a Si(111). PL spectrum peak near 1.3 μm indicates that such system is promising for optoelectronic devices.

Management of light and scattering in InP NWs by dielectric polymer shell

Understanding and management of light is of great importance for nanoscale devices. This report demonstrates enhanced absorption, photoluminescence and scattering in InP nanowires when coated with dielectric polymer shell. The shells increase absorption and emission by a factor of ∼2 and photoluminescence by a factor of ∼4. A thorough optical characterization is provided, including reflectance, transmission, luminescence and scattering to incident and transmitted directions. From this characterization, we derive the distribution of absorbed light within the structure (InP nanowires, Au seed particles and the substrate). Additionally, reflectance, transmission and emission are shown to become increasingly diffuse with the dielectric shells. The results are thought to provide better understanding in light–matter interaction in nanostructures, as well as to provide valuable tools for light and scattering management in nanoscale optoelectronics.

Atomistic investigations on the mechanical properties and fracture mechanisms of indium phosphide nanowires.

The mechanical properties of indium phosphide (InP) nanowires are an emerging issue due to the promising applications of these nanowires in nanoelectromechanical and microelectromechanical devices. In this study, molecular dynamics simulations of zincblende (ZB) and wurtzite (WZ) crystal structured InP nanowires (NWs) are presented under uniaxial tension at varying sizes and temperatures. It is observed that the tensile strengths of both types of NWs show inverse relationships with temperature, but are independent of the size of the nanowires. Moreover, applied load causes brittle fracture by nucleating cleavage on ZB and WZ NWs. When the tensile load is applied along the [001] direction, the direction of the cleavage planes of ZB NWs changes with temperature. It is found that the {111} planes are the cleavage planes at lower temperatures; on the other hand, the {110} cleavage planes are activated at elevated temperatures. In the case of WZ NWs, fracture of the material is observed to occur by cleaving along the (0001) plane irrespective of temperature when the tensile load is applied along the [0001] direction. Furthermore, the WZ NWs of InP show considerably higher strength than their ZB counterparts. Finally, the impact of strain rate on the failure behavior of InP NWs is also studied, and higher fracture strengths and strains at higher strain rates are found. With increasing strain rate, the number of cleavages also increases in the NWs. This paper also provides in-depth understanding of the failure behavior of InP NWs, which will aid the design of efficient InP NWs-based devices.

Diameter Dependence of Planar Defects in InP Nanowires.

In this work, extensive characterization and complementary theoretical analysis have been carried out on Au-catalyzed InP nanowires in order to understand the planar defect formation as a function of nanowire diameter. From the detailed transmission electron microscopic measurements, the density of stacking faults and twin defects are found to monotonically decrease as the nanowire diameter is decreased to 10 nm, and the chemical analysis clearly indicates the drastic impact of In catalytic supersaturation in Au nanoparticles on the minimized planar defect formation in miniaturized nanowires. Specifically, during the chemical vapor deposition of InP nanowires, a significant amount of planar defects is created when the catalyst seed sizes are increased with the lower degree of In supersaturation as dictated by the Gibbs-Thomson effect, and an insufficient In diffusion (or Au-rich enhancement) would lead to a reduced and non-uniform In precipitation at the NW growing interface. The results presented here provide an insight into the fabrication of “bottom-up” InP NWs with minimized defect concentration which are suitable for various device applications.

Optical mode study of III–V-nanowire-based nanophotonic crystals for an integrated infrared band microlaser

In this paper, we study an original strategy to generate an infrared waveband microlaser by an integrated III–V-nanowire (NW)-based photonic array for on-chip interconnects. The optical modes of the III–V-NW-based photonic array are investigated for utilization as an all-in-one gain medium, waveguide, and cavity. Adequate designs of periodic arrays of InP NWs with different polarization TM and TE modes are studied by 3D electromagnetic simulation finite difference time domain to optimize the resonant active photonic crystal (hybrid Bloch modes) in the infrared band at 1.3 μm. According to our calculations, NWs larger than 0.2 μm in diameter are needed to conceive optic modes inside NW photonics in TM polarization. However, smaller NW photonics, such as 0.1 μm in diameter, can obtain only the TE mode inside the NWs. This phenomenon is theoretically illustrated by the dispersive curves of NW-based photonics. It aims at demonstrating that the slow velocity mode inside the NW photonics will cause amplification of lightwaves and generate microlasers in the infrared band at 1.3 μm. These studies are of prime importance for further microlaser integration to silicon-on-insulator (SOI) waveguides for on-chip optical interconnects.

Growth and characterization of indium phosphide nanowires on transparent conductive ZnO:Al films

The epitaxial growth of indium phosphide nanowires (InP NWs) on transparent conductive aluminum-doped zinc oxide (ZnO:Al) thin films is proposed and demonstrated. ZnO:Al thin films were prepared on quartz substrates by radio frequency magnetron sputtering, then InP NWs were grown on them by plasma enhanced metal organic chemical vapor deposition with gold catalyst. Microstructure and optical properties of InP nanowires on ZnO:Al thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectric spectroscopy (XPS), photoluminescence and Raman spectroscopy at room temperature. SEM shows that randomly oriented and intersecting InP nanowires were grown to form a network on ZnO:Al thin films. Both wurtzite (WZ) and zincblende (ZB) structures coexist in the random orientation InP NWs on ZnO:Al thin film had been proved by XRD analysis. XPS result indicates Zn diffusion exists in the InP NWs on ZnO:Al. The photoluminescence spectra of InP nanowires with Zn diffusion present an emission at 915 nm. Zn diffusion also bring effect on Raman spectra of InP NWs, leading to more Raman-shift and larger relative intensity ratio of TO/LO.

High-performance indium phosphide nanowires synthesized on amorphous substrates: from formation mechanism to optical and electrical transport measurements

InP NWs have been extensively explored for next-generation electronic and optoelectronic devices due to their excellent carrier mobility, exciton lifetime and wave-guiding characteristics. Typically, those NWs are grown epitaxially on crystalline substrates which could limit their potential applications requiring high growth yield to be printable or transferable on amorphous and flexible substrates. Here, utilizing Au as catalytic seeds, we successfully demonstrate the synthesis of crystalline, stoichiometric and dense InP NWs on amorphous substrates. Notably, the NWs are found to grow via the vapor–liquid–solid (VLS) mechanism with a narrow distribution of diameter (34.6 ± 7.7 nm) uniformly along the entire NW length (>10 μm). Although the grown NWs possess a substantial amount of twin defects, the fabricated NW FETs still exhibit impressive electrical performance with high carrier mobility (∼350 cm2 V−1 s−1) and ION/IOFF ratio (∼106). All these have demonstrated the promising potency of such NWs grown on amorphous substrates for technological applications, as compared to the conventional MBE or MOCVD grown InP NWs.

Electronics and Photonics Integration on Non-Crystalline Substrates via Nanoheteroepitaxy

The ability to grow dissimilar materials with large lattice mismatches on a single substrate removes the integration related constraints of incorporating photonics with electronics. We review our recent nanoheteroepitaxy efforts on the epitaxial growth of bridged InP NWs between two vertical, (111)-oriented Si surfaces by forming connections during the NW growth facilitating their direct electrical probing via Si electrodes and a new method of synthesizing III-V NWs on a non-single crystalline surface that directly relaxes any lattice matching conditions. The current-voltage behavior with temperature and the resulting photo-enhanced thermal failure is also discussed.

Synthesis, characterization and photoconductivity of highly crystalline InP nanowires prepared from solid hydrogen phosphide

Download options Please wait... Supplementary files TEM images of Bi nanoparticles, SEM image of InP NWs as a matand electron diffraction pattern for growth directionanalysis PDF (2491K) Article information DOI https://doi.org/10.1039/B902474C Article type Paper Submitted 05 Feb 2009 Accepted 23 Apr 2009 First published 28 May 2009 Download Citation J. Mater. Chem., 2009,19, 4852-4856 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Synthesis, characterization and photoconductivity of highly crystalline InP nanowires prepared from solid hydrogen phosphide T. H. Lim, S. Ravi, C. W. Bumby, P. G. Etchegoin and R. D. Tilley, J. Mater. Chem., 2009, 19, 4852 DOI: 10.1039/B902474C To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Teck H. Lim Shrividya Ravi Christopher W. Bumby Pablo G. Etchegoin Richard D. Tilley

Hydrogenated microcrystalline silicon electrodes connected by indium phosphide nanowires

The authors report the connection of two planar hydrogenated silicon (Si:H) electrodes by intersecting and bridging indium phosphide nanowires (InP NWs). A simple metal-semiconductor-metal photoconductor was used as a test vehicle to measure electrical and optical characteristics of the connected InP NWs. This implementation of III-V compound semiconductor nanowires on Si:H combines the characteristics of a direct bandgap semiconductor with the flexible fabrication processes of non-single-crystal silicon platforms that do not require single-crystal substrates.

Size-Dependent Photoluminescence from Single Indium Phosphide Nanowires

Photoluminescence (PL) imaging and spectroscopy have been used to investigate isolated, individual indium phosphide nanowires (InP NWs) at both room temperature and 7 K. PL images and spectra show that the emission maxima, line shapes, and intensities are nearly identical along the axis of a given NW. PL spectra collected on InP NWs with diameters of 10, 15, 20, and 50 nm show that emission maxima systematically shift to higher energy with decreasing wire diameter, for diameters less than 20 nm. An effective mass model (EMM) has been developed using particle-in-a-cylinder wave functions for electrons and holes to explore quantitatively the diameter-dependent PL data. The EMM provides excellent fits to the diameter-dependent data obtained at both room temperature and 7 K, and shows that the shifts in the emission spectra can be explained by radial quantum confinement.