Study on Raman spectroscopy of InSb nano-stripes grown on GaSb substrate by molecular beam epitaxy and their Raman peak shift with magnetic field (original) (raw)
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Growth and Photoluminescence Properties of InSb/GaSb Nano‐Stripes Grown by Molecular Beam Epitaxy
physica status solidi (a), 2018
We report the growth and photoluminescence (PL) properties of InSb/GaSb nano-stripes grown by molecular beam epitaxy on (001) GaSb substrate. In situ reflection high-energy electron diffraction observation during InSb growth shows that the growth of InSb on GaSb surface is in Stranski-Krastanov mode and results in nano-stripe formation. The obtained nano-stripes have rectangular-based with the height of 25.2±4.0 nm and they are elongated along [110] direction. PL emission from buried InSb/GaSb nano-stripes shows the emission peak at ~1850 nm (0.67 eV). According to the emission energy and the structural information, low In content of ~0.24 in nominally grown InSb/GaSb nano-stripe is estimated. Powerdependent PL spectroscopy shows a linear relation between integrated PL intensity and the excitation power. and the laser power without any signature of intensity saturation. Thermal activation energy of ~20 meV from InSb nano-stripe emission is extracted from the temperature-dependent PL spectroscopy.
Journal of Crystal Growth, 2019
Distinct InSb/InAs quantum nano-stripes possessing type-II band alignment with a broken gap are grown using molecular beam epitaxy with low substrate temperature and slow growth rate, aiming for light emission in a mid-infrared range. The quantum nano-stripes are shown to emit light at a wavelength of 3.1 µm. The excitation power dependence of photoluminescence spectra from the quantum nano-stripes reveals a clear linear blueshift with the third root of the excitation power, which is a unique property of the quantum nanostructures with type-II band alignment. The demonstrated mid-infrared light emission from the InSb/InAs quantum nano-stripes would offer a promising pathway for realizing practical, highly-efficient, and room-temperature-operating midinfrared light sources and detectors.
GaSb and InSb Quantum Nanostructures: Morphologies and Optical Properties
MRS Advances, 2015
ABSTRACTGaSb/GaAs and InSb/GaAs material systems can create type-II quantum nanostructures which provide interesting electronic and optical properties such as having long carrier life time, low carriers-recombination rate, and emitting/absorbing low photon energy. These characteristics of type-II nanostructures can be applied for infrared or gas detection devices, for memory devices and even for novel intermediate band solar cells. In contrast, lattice mismatches of GaSb/GaAs and InSb/GaAs material system are 7.8% and 14.6%, respectively, which need some specific molecular beam epitaxial (MBE) growth conditions for quantum nanostructure formation via Stranski–Krastanov growth mode.In this paper, the growth of self-assembled GaSb and InSb quantum nanostructures on (001) GaAs substrate by using MBE was reported. The surface morphology of these two quantum nanostructures and their optical properties were characterized by atomic force microscopy and photoluminescence (PL). The experimen...
Raman scattering of InSb quantum dots grown on InP substrates
Journal of Applied Physics, 1997
In this paper we present the Raman scattering of self-assembled InSb dots grown on (001) oriented InP substrates. The samples were grown by pulsed molecular beam epitaxy mode. Two types of samples have been investigated. In one type the InSb dots were capped with 200 monolayers of InP; in the other type no capping was deposited after the InSb dot formation. We observe two peaks in the Raman spectra of the uncapped dot, while only one peak is observed in the Raman spectra of the capped dots. In the case of the uncapped dots the peaks are attributed to LO-like and TO-like vibration of completely relaxed InSb dots, in agreement with high resolution transmission electron microscopy photographs. The Raman spectra of the capped dot suggest a different strain state in the dot due to the capping layer.
Molecular-beam epitaxy of InSb/GaSb quantum dots
(2007) Journal of Applied Physics, 101 (12), art. no. 124309, .
We have investigated the molecular-beam epitaxy (MBE) of InSb nanostructures on (100) GaSb substrates. We show that MBE leads to a low density (∼1-3× 109 cm-2) of large islands even when varying the growth conditions on a wide range (substrate temperature ∼370-450 °C, growth rate ∼0.3-1.2 MLs). Plastic relaxation takes place from the onset of island formation, regardless of the amount of InSb deposited after the two-dimensional to three-dimensional transition. These results show that In adatoms have a very long diffusion length on a Sb-terminated surface and that the energy for dislocation generation in InSb is low. This can be attributed to the low enthalpy of formation and low melting point of InSb. To circumvent this problem we have developed a MBE growth procedure based on the deposition of an amorphous InSb layer at low temperature followed by an annealing step to allow for reorganization to take place. This dramatic change of the growth conditions leads to the formation of small InSb quantum dots with a density in excess of 7× 1010 cm-2. Uncapped quantum dots, however, are relaxed. In contrast, buried quantum dots are fully strained and emit near 3.5 μm at room temperature. Our results show that although formerly similar the InSb/GaSb materials system behaves completely differently from the InAs/GaAs case study system.
Nanoscale Research Letters, 2013
Vertically aligned single-crystal InSb nanowires were synthesized via the electrochemical method at room temperature. The characteristics of Fourier transform infrared spectrum revealed that in the syntheses of InSb nanowires, energy bandgap shifts towards the short wavelength with the occurrence of an electron accumulation layer. The current–voltage curve, based on the metal–semiconductor–metal model, showed a high electron carrier concentration of 2.0 × 1017 cm−3 and a high electron mobility of 446.42 cm2 V−1 s−1. Additionally, the high carrier concentration of the InSb semiconductor with the surface accumulation layer induced a downward band bending effect that reduces the electron tunneling barrier. Consequently, the InSb nanowires exhibit significant field emission properties with an extremely low turn-on field of 1.84 V μm−1 and an estimative threshold field of 3.36 V μm−1.
Fabrication and optical property of single-crystalline InSb nanowire arrays
Journal of Materials Science, 2007
Semiconductor InSb nanowire arrays have been synthesized by the pulsed electrochemical deposition from citric acid aqueous solution into anodic alumina membranes. It was found that the InSb nanowires are of zinc-blende structure, and high filling rate and single-crystalline InSb nanowire array with right stoichiometric composition can be fabricated by proper controlling of the concentration of In and Sb ions and the PH value in the electrolyte and the pulse voltage, and the nanowires have [100] orientation with structure defects such as twins. The optical band gap has a strong blue shift with decreasing the diameter of the nanowire due to the quantum confinement effect.
Measurements of light absorption efficiency in InSb nanowires
Structural Dynamics, 2013
We report on measurements of the light absorption efficiency of InSb nanowires. The absorbed 70 fs light pulse generates carriers, which equilibrate with the lattice via electron-phonon coupling. The increase in lattice temperature is manifested as a strain that can be measured with X-ray diffraction. The diffracted X-ray signal from the excited sample was measured using a streak camera. The amount of absorbed light was deduced by comparing X-ray diffraction measurements with simulations. It was found that 3.0(6)% of the radiation incident on the sample was absorbed by the nanowires, which cover 2.5% of the sample. V
Molecular beam epitaxy growth of InSb/GaAs quantum nanostructures
Journal of Crystal Growth, 2017
InSb/GaAs nanostructures grown by solid-source molecular beam epitaxy are investigated in this work. Threedimensional dot-like InSb nanostructures are obtained by self-assembled growth at relatively low growth temperatures (250-300°C) with slow InSb growth rate. Nanostructure base is typically elongated. Facet analysis of the free-standing InSb nanostructure grown at 250°C shows that each nanostructure has flat top (001) surface while side facets are along < 11n > directions. In contrast, InSb nanostructures grown at higher temperature show rather smooth surfaces. Analysis of their size distributions shows that the size inhomogeneity increases with the growth temperature. Moreover, Raman spectroscopy reveals both InSb-related peaks at 181 and 189 cm −1 and GaAs-related peaks at 268 and 293 cm −1. Raman spectroscopy with different excitation wavelengths is applied to probe residual strain in subsurface GaAs layer.