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Showing papers on "Antimonide published in 2012"


Journal ArticleDOI
TL;DR: A combined scanning electron microscope, transmission electron microscopy, and scanning tunneling microscopy study of gold-nucleated ternary InAs/InAs(1-x)Sb(x) nanowire heterostructures grown by molecular beam epitaxy finds correlation of the morphological and structural properties of the nanowires with the amount of Sb incorporated during growth.
Abstract: III‐V antimonide nanowires are among the most interesting semiconductors for transport physics, nanoelectronics and long-wavelength optoelectronic devices due to their optimal material properties. In order to investigate their complex crystal structure evolution, faceting and composition, we report a combined scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning tunneling microscopy (STM) study of gold-nucleated ternary InAs/InAs1 xSbx nanowire heterostructures grown by molecular beam epitaxy. SEM showed the general morphology and faceting, TEM revealed the internal crystal structure and ternary compositions, while STM was successfully applied to characterize the oxide-free nanowire sidewalls, in terms of nanofaceting morphology, atomic structure and surface composition. The complementary use of these techniques allows for correlation of the morphological and structural properties of the nanowires with the amount of Sb incorporated during growth. The addition of even a minute amount of Sb to InAs changes the crystal structure from perfect wurtzite to perfect zinc blende, via intermediate stacking fault and pseudo-periodic twinning regimes. Moreover, the addition of Sb during the axial growth of InAs/InAs1 xSbx heterostructure nanowires causes a significant conformal lateral overgrowth on both segments, leading to the spontaneous formation of a core‐shell structure, with an Sb-rich shell.

115 citations


Journal ArticleDOI
TL;DR: In this paper, the authors performed hybrid density functional calculations for single-layer boron pnictides and showed that these materials exhibit a direct bandgap of 6.1, 1.4, 0.6, and 1.2, respectively.
Abstract: Single-layer materials such as graphene and boron nitride promise alternative routes to electronic devices. Hybrid density functional calculations for single-layer boron pnictides boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), and boron antimonide (BSb) show that these materials exhibit a direct bandgap of 6.1, 1.4, 1.2, and 0.6 eV, respectively, that originates from the energy difference of the pz orbitals of the species and is tunable by strain. The bandgap linearly decreases with strain for BN, while it increases non-linearly for BP, BAs, and BSb. The calculated natural band offsets between the various boron pnictides are all of type I.

106 citations


Journal ArticleDOI
TL;DR: It is shown that it is possible to regrow InAs above the InAsSb alloy segment, at least up to an intermediate antimony composition, and the nucleation and step-flow mechanism leading to this lateral growth has been identified and described.
Abstract: We report the growth of InAs/InAs1−xSbx single and double heterostructured nanowires by Au-assisted chemical beam epitaxy. The InAs1−xSbx nanowire segments have been characterized in a wide range of antimony compositions. Significant lateral growth is observed at intermediate compositions (x ~ 0.5), and the nucleation and step-flow mechanism leading to this lateral growth has been identified and described. Additionally, CuPt ordering of the alloy has been observed with high resolution transmission electron microscopy, and it is correlated to the lateral growth process. We also show that it is possible to regrow InAs above the InAsSb alloy segment, at least up to an intermediate antimony composition. Such double heterostructures might find applications both as mid-infrared detectors and as building blocks of electronic devices taking advantage of the outstanding electronic and thermal properties of antimonide compound semiconductors.

53 citations


Journal ArticleDOI
TL;DR: In this paper, an antimonide quantum-well diode laser was used as an excitation source for a methane sensor based on quartz-enhanced photoacoustic spectroscopy.
Abstract: A methane sensor based on quartz-enhanced photoacoustic spectroscopy was developed. An antimonide quantum-well diode laser was used as an excitation source. The GaInAsSb/AlGaAsSb laser was fabricated by molecular beam epitaxy on GaSb substrate. This diode laser emits in the 2.35 μm range at room temperature in the continuous wave regime. A spectrophone constituted of a quartz tuning fork and two steel microresonators was used. The analysis of the sensor response with one, two or without microresonators is presented. Second derivative wavelength modulation detection was used to perform low concentrations measurements, thus we obtained a CH4 detection limit of 1 ppmv.

28 citations


Proceedings ArticleDOI
05 Oct 2012
TL;DR: In this article, the authors compared dilute nitride GaInNAs and Sb solar cells grown by molecular beam epitaxy and found that Sb-containing cells showed inferior properties to those without it.
Abstract: We compare dilute nitride GaInNAs and GaInNAsSb solar cells grown by molecular beam epitaxy. Single junction p-i-n diode solar cells were fabricated to test the dilute nitride and antimonide material fabrication process. Triple-junction solar cells were fabricated to test the behavior of single GaInNAs(Sb) junctions in multi-junction configuration. When nitrogen was added to the growth of GaInNAs, good crystal quality was maintained up to 4% of nitrogen at the used growth conditions. Short circuit current densities of the devices could be increased by adding Sb to the growth but at the same time the open circuit voltages decreased due to bandgap shrinkage induced by Sb. In multijunction configuration, the samples with Sb showed inferior properties to ones without it. Lower currents and voltages of Sb-containing cells may be linked to segregation of Sb and transfer to the upper junctions.

13 citations


Patent
20 Jun 2012
Abstract: The invention discloses an antimonide transistor with high electron mobility, which comprises a substrate, a composite buffer layer, an antimonide lower barrier layer, a channel layer, an antimonide isolated layer, a doping layer, an upper barrier layer and a cap layer, wherein the composite buffer layer grows on the substrate; the antimonide lower barrier layer grows on the composite buffer layer; the channel layer grows on the antimonide lower barrier layer; the antimonide isolated layer grows on the channel layer; the doping layer grows on the antimonide isolated layer; the upper barrier layer grows on the doping layer; and the cap layer grows on the upper barrier layer. The invention discloses a method for manufacturing the antimonide transistor with the high electron mobility. In theantimonide transistor, by adopting the composite buffer layer, the quality of transistor structural materials is improved greatly, the electronic transport characteristic of a channel is better, the output characteristic of the device is improved, the characteristics of high frequency, high speed and low power consumption of the device is fully played, and the stability and reliability of the device are improved effectively.

10 citations


Journal ArticleDOI
TL;DR: In this article, the suppression of interface state response using band engineering in III-V quantum well MOSFETs was investigated and experimentally verified in the antimonide materials system using a gate-stack consisting of Al2O3/GaSb/InAlSb.
Abstract: Performance degradation due to interfacial traps is generally considered as one of the main challenges for III-V metal-oxide-semiconductor field-effect-transistors (MOSFETs). In this work, we have investigated the suppression of interface state response using band engineering in III-V quantum well MOSFETs and experimentally verified the concept in the antimonide materials system using a gate-stack consisting of Al2O3/GaSb/InAlSb. It is shown that if the thickness of the interfacial layer of GaSb is scaled down to a few monolayers, the effective bandgap of the interfacial layer increases dramatically due to quantum confinement, which leads to the suppression of interface-trap response.

8 citations


Patent
08 Aug 2012
TL;DR: In this article, an epitaxial growth method of a W type antimonide class II quantum well is described, which comprises the following steps: step 1) selecting a substrate, step 2) performing deoxidation and degasification treatment on the substrate, and step 3) sequentially growing a buffer layer.
Abstract: The invention relates to an epitaxial growth method of a W type antimonide class II quantum well, which comprises the following steps: step 1) selecting a substrate; step 2) performing deoxidation and degasification treatment on the substrate, and observing the surface reconstruction; and step 3) sequentially growing a buffer layer, a W-structured class II quantum well active area with 10 cycles and a GaSb cover layer on the substrate

7 citations


Proceedings ArticleDOI
12 Jun 2012
TL;DR: In this article, the authors have demonstrated that Sb NMOS exhibits effective electron mobility of 6,000 cm2/Vs at high field (2 × 1012 /cm2 of charge density (N s )), which is the highest reported value for any III-V MOSFET.
Abstract: Antimonide (Sb) quantum well (QW) MOSFETs are demonstrated with integrated high-к dielectric (1nmAl 2 O 3 –10nm HfO 2 ). The long channel Sb NMOS exhibits effective electron mobility of 6,000 cm2/Vs at high field (2 × 1012 /cm2 of charge density (N s )), which is the highest reported value for any III–V MOSFET. The short channel Sb NMOSFET (L G = 150nm) exhibits a cut-off frequency (f T ) of 120GHz, f T - L G product of 18GHz.µm and source side injection velocity (v eff ) of 2.7×107 cm/s, at drain bias (V DS ) of 0.75V and gate overdrive of 0.6V. The measured f T and f T × L G are 2 x higher, and v eff is 4x higher than Si NMOS (1.0–1.2V V DD ) at similar L G , and are the highest for any III–V MOSFET.

6 citations


Journal ArticleDOI
TL;DR: In this paper, an excitation source on a methane sensor based on quartz-enhanced photoacoustic spectroscopy was used, and a detection limit of 400 ppbv was achieved using second derivative wavelength modulation detection.
Abstract: GaInAsSb/AlGaAsSb quantum wells lasers have been grown by molecular beam epitaxy and processed into ridge cavities coupled by an intracavity photonic crystal mirror. The lasers operate at room temperature in the continuous wave regime at 2.35 m. One of these devices was used as an excitation source on a methane sensor based on quartz-enhanced photoacoustic spectroscopy. A spectrophone, consisting of a quartz tuning fork and two steel microresonators, was used. A detection limit of 400 ppbv was achieved using second derivative wavelength modulation detection.

6 citations


Journal ArticleDOI
TL;DR: In this article, the performance of UV electroabsorption modulators based on bulk GaN films and GaN/AlGaN multiple quantum wells was compared and compared to the case of arsenide, phosphide, or antimonide semiconductors, where the absorption effect in quantum wells is an order of magnitude stronger than in the bulk.
Abstract: In this paper we present studies and compare the performance of UV electroabsorption modulators based on bulk GaN films and GaN/AlGaN multiple quantum wells. In both types of devices, the absorption edge at room temperature is dominated by excitonic effects and can be strongly modified through the application of an external electric field. We find that when similar active layer thicknesses and device geometries are employed, the electroabsorption modulators based on bulk nitride films can provide similar performance levels as those of GaN/AlGaN multiple quantum well devices. This should be compared to the case of arsenide, phosphide, or antimonide semiconductors, where the electroabsorption effect in quantum wells is an order of magnitude stronger than in the bulk. This is primarily due to the strong ionic character of the nitride semiconductors, which lead to very large exciton binding energies at room temperature (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Journal ArticleDOI
TL;DR: In this paper, a large quantity of cobalt antimonide (CoSb3) based skutterudites nanopowder (NP) was fabricated through a room temperature co-precipitation precursor method.
Abstract: Skutterudites are known to be efficient thermoelectric (TE) materials in the temperature range from 600 K to 900 K. Dimensionless figure of merit (ZT) for filled skutterudite TE materials have been reported as ca. 1 at 800 K. Novel nano- engineering approaches and filling of the skutterudites crystal can further improve the transport properties and ultimately the ZT. Although classified among the promising TE materials, research on their large-scale production via bottom up synthetic routes is rather limited. In this work, large quantity of cobalt antimonide (CoSb3) based skutterudites nanopowder (NP) was fabricated through a room temperature co-precipitation precursor method. Dried precipitates were process by thermo-chemical treatment steps including calcination (in air) and reduction (in hydrogen). CoSb3 NPs were then mixed with silver (Ag) nanoparticles at different weight percentages (1%, 5% and 10% by wt) to form nanocomposites. Skutterudite NP was then consolidated by Spark Plasma Sintering (SPS) technique to produce highly dense compacts while maintaining the nanostructure. Temperature dependent TE characteristics of SPS’d CoSb3 and Ag containing nanocomposite samples were evaluated for transport properties, including thermal conductivity, electrical conductivity and Seebeck coefficient over the temperature range of 300 - 900 K. Physicochemical, structural and microstructural evaluation results are presented in detail.


Patent
02 May 2012
TL;DR: In this paper, a designing method of an InAs/GaSb superlattice electronic structure with an M-shaped barrier layer with Al (Ga) Sb is presented, which belongs to the technical field of electronic structure design of plane infrared probe materials.
Abstract: The invention discloses a designing method of an InAs/GaSb superlattice electronic structure with an M-shaped barrier layer, which belongs to the technical field of electronic structure design of plane infrared probe materials The InAs/GaSb superlattice electronic structure is made of a material of a focal plane infrared provided with the InAs/GaSb superlattice electronic structure An experience tight binding method is adopted, tight binding parameters are determined through non-linear least square fitting, and design of the InAs/GaSb superlattice electronic structure with the M-shaped barrier layer with Al (Ga) Sb is carried out Simultaneously, influence of an Al component on superlattice photoelectric performance is studied, and design of the M-shaped InAs/GaSb superlattice with an AlGaSb barrier layer is achieved Molecular beam epitaxy growing technological conditions are simplified, and component fluctuation caused in a growing process is reduced The designing method of the InAs/GaSb superlattice electronic structure has an important effect of promoting application of antimonide semiconductor low dimensional neterogeny structure in the field of photoelectric detection and thermophotovoltaic battery

Patent
10 Oct 2012
TL;DR: In this paper, a high-wavelength antimonide semiconductor laser structure has been proposed to improve the performance of the laser, which has the characteristics of low optical mode loss and strong cavity restrictions.
Abstract: The invention discloses a high-wavelength antimonide semiconductor laser structure, which belongs to the field of epitaxial structures made from novel materials for semiconductor lasers and aims at the problems and shortcomings that the power, efficiency and the like of an antimonide laser are lowered along with the increasing of wavelengths. The laser structure can alleviate the problem that thepower and efficiency of the laser are lowered due to free charge carrier absorption and the like, has the characteristics of low optical mode loss, strong cavity restrictions, low internal loss, highquantum well laser structure efficiency and the like, and can improve the performance of the antimonide laser such as the power, the efficiency and the like.

Patent
20 Jun 2012
TL;DR: In this paper, a molecular beam epitaxial growth method of InAs/GaAsSb quantum dots, belonging to the field of the preparation technology of photoelectric devices, is described.
Abstract: The invention discloses a molecular beam epitaxial growth method of InAs/GaAsSb quantum dots, belonging to the field of the preparation technology of photoelectric devices. The method comprises the following steps of: firstly preparing a GaAsSb alloy thin layer with low antimony content; and then preparing stress self-assembly GaAs-based InAs/GaAsSb quantum dots by use of the molecular beam epitaxial growth technology for growing InAs quantum dots. In the method, the growth process is determined by thermodynamic parameters, the prepared GaAsSb alloy suffers little influence of technological conditions, the components are easy to control, controllable-density InAs/GaAsSb quantum dots are obtained, and a foundation is laid for the application of antimonide alloy-based InAs quantum dots in the fields of solar cells, photoelectric detectors and the like.

Dissertation
01 Jan 2012
TL;DR: In this paper, the authors investigated the growth and application of antimonide heterostructure nanowires for low-power electronics, and the performance of GaSb/InAs(Sb) tunnel diodes was modeled and measured on fabricated single nanowire devices.
Abstract: in Undetermined This thesis investigates the growth and application of antimonide heterostructure nanowires for low-power electronics. In the first part of the thesis, GaSb, InSb and InAsSb nanowire growth is presented, and the distinguishing features of the growth are described. It is found that the presence of Sb results in more than 50 at. % group-III concentration in the Au seed particle on top of the nanowires. It is further concluded that the effective V/III ratio inside the seed particle is reduced compared to the outside. This enables the suppression of radial growth with remaining high axial growth rate. Furthermore, the low effective V/III ratio may affect the crystal structure formation, which is pure Zinc-blende in all investigated Sb-based nanowires. The strong segregating properties of Sb results in a strong Sb memory effect, and a difficulty to nucleate Sb-based nanowires directly on substrates. The second part of the thesis deals with the growth and application of GaSb/InAs(Sb) nanowires for tunnel device applications. The GaSb/InAs(Sb) nanowire heterojunction has a defect-free crystal structure with an extremely abrupt heterojunction due to an inherent delay before the initiation of InAs(Sb) growth. The Sb carry-over from the GaSb growth step into the InAs growth leads to a high Sb background in the InAs(Sb) segment. The diameter of the heterojunction can be reduced below 30 nm by an in-situ annealing treatment, in which material is selectively etched from the region near the heterojunction. The performance of GaSb/InAs(Sb) tunnel diodes is modeled and measured on fabricated single nanowire devices. The diodes exhibit peak current levels of 67 kA/cm^{2} , peak-to-valley current ratio between 2 and 3 at room temperature and a tunnel current at V_{D} = -0.5 V of 1.7 MA/cm^{2} . The expected performance of GaSb/InAs(Sb) tunnel field-effect transistors is discussed and preliminary measurement data on top-gated devices with 300 nm gate length is also presented. (Less)

Proceedings ArticleDOI
01 Dec 2012
TL;DR: In this paper, the authors presented a lowvoltage highspeed antimonide-based compound semiconductor (ABCS) high electron-mobility transistor (HEMT) monolithic microwave integrated circuit (MMIC) process and its single-pole double-throw (SPDT) broadband switch application.
Abstract: In this paper, we present a low-voltage highspeed antimonide-based compound semiconductor (ABCS) high electron-mobility transistor (HEMT) monolithic microwave integrated circuit (MMIC) process and its single-pole double-throw (SPDT) broadband switch application. The measured 3-dB bandwidth of the proposed SPDT switch is from dc to 30 GHz. The switch features an insertion loss of less than 4 dB, and an isolation of greater than 18 dB between 10 MHz and 30 GHz. The measured input 1 dB compression point (P 1dB ) and third-order intercept point (IP3) at 100 MHz are 12.5 and 27 dBm, respectively. The chip size of the proposed switch is 0.75 × 0.58 mm2. These results demonstrate the outstanding potential of ABCS HEMT technology for low voltage switch applications.

Proceedings ArticleDOI
01 Dec 2012
TL;DR: In this paper, the authors presented the model of a Type-II InAs/GaSb Superlatttice with experimentally verified dimensions and parameters, where the Transfer Matrix Method (TMM) has been adopted to represent the wave function solution under zero bias and non-zero bias respectively.
Abstract: In recent times, the Type-II InAs/GaSb Superlatttice has been opted as a viable replacement for HgCdTe based photodetectors as the band structure of these devices can be tailored. Significant progress has been made and ongoing research is being conducted in the growth and characterization of these devices. We present the model of such a device with experimentally verified dimensions and parameters. The Transfer Matrix Method (TMM) has been adopted to represent the wave function solution under zero bias and non-zero bias respectively. Cutoff wavelength of 10µm range was achieved. These devices have the added advantage of tunability with respect to well width and bias voltages and have attractive applications in optical switching.

Journal ArticleDOI
TL;DR: In this paper, the emitter size effect of a series InGaAsSb base series of InP/InGaASb/INGaAs heterojunction bipolar transistors (HBTs) with different emitter sizes is investigated.
Abstract: The emitter size effect of a series InGaAsSb base series of InP/InGaAsSb/InGaAs heterojunction bipolar transistors (HBTs) with different emitter sizes is investigated. Compared to the InGaAs base HBTs, these devices exhibit much lower base surface recombination current. This is attributed to the surface Fermi level pinning near the valence band of the antimonide base. The effect of Sb composition and doping concentration of the base on the surface recombination current is well explained by the postulate.

20 May 2012
TL;DR: In this paper, the authors have grown multi-alkali antimonide cathodes on (100) silicon substrates, simultaneously acquiring in-situ X-ray diffraction (XRD) and Xray reflection (XRR) data throughout the growth process.
Abstract: Alkali antimonide cathodes have the potential to provide high quantum efficiency for visible light and are significantly more tolerant of vacuum contaminants than GaAs, so they are attractive for use in high-average- current photoinjectors to generate high quality electron beams. We have grown multi-alkali cathodes on (100) silicon substrates, simultaneously acquiring in-situ X-ray diffraction (XRD) and X-ray reflection (XRR) data throughout the growth process. Correlations between cathode structure and growth parameters and the resulting quantum efficiency (QE) have been explored.

Journal ArticleDOI
TL;DR: In this article, an ex-situ monitoring technique based on glancing-angle infrared-absorption was used to determine small amounts of erbium antimonide (ErSb) deposited on an indium-antimonide layer epitaxially grown on an InSb (100) substrate by low pressure metal organic chemical vapor deposition.

Proceedings ArticleDOI
TL;DR: In this paper, growth and device performance of infrared photodetectors based on type II InAs/Ga(In)Sb strain layer superlattices (SLs) using the complementary barrier infrared detector (CBIRD) design is reported.
Abstract: The closely lattice-matched material system of InAs, GaSb, and AlSb, commonly referred to as the 6.1A material system, enables many unique approaches for producing high performance infrared detectors. The flexibility of the materials system allows for superlattice structures that can be tailored to have cutoff wavelengths ranging from the short wave infrared to the very long wave infrared. The type-II superlattice design promises high optical properties due to normal incidence absorption, high uniformity, low tunneling currents, and suppressed Auger recombination. The antimonide material system also allows for the design of high performance barrier structures. In particular, unipolar barriers, which blocks one carrier type without impeding the flow of the other, have been implemented in the design of SL photodetectors to realize complex heterodiodes with improved performance. Here we report on growth and device performance of infrared photodetectors based on type II InAs/Ga(In)Sb strain layer superlattices (SLs) using the complementary barrier infrared detector (CBIRD) design.


Proceedings ArticleDOI
26 Nov 2012
TL;DR: In this article, the authors proposed a growth of antimonide vertical external cavity surface emitting laser (VECSEL) for 1.8 to 2.8 µm emission wavelength is typically based on InGaSSb/AlGaAsSb quantum wells.
Abstract: The growth of antimonide vertical external cavity surface emitting lasers (VECSELs) for 1.8 to 2.8 µm emission wavelength is typically based on InGaAsSb/AlGaAsSb quantum wells on GaSb/AlAsSb DBRs which are in turn grown on GaSb substrates. Thus the entire structure is lattice matched to GaSb's lattice constant of 6.09 A. The growth of such VECSELs on GaAs/AlGaAs DBRs could be of significant advantage on account of a more mature DBR technology based on GaAs substrates, better thermal conductivity of the III-As DBRs compared to the III-Sb DBRs and better etch stop recipes for arsenide semiconductors compared to antimonides. However, the growth of such a laser would involve overcoming a 7.8% mismatch between the active region and the GaAs/AlGaAs DBR. Furthermore, the vertical cavity structure requires the quantum wells to be in very close proximity to the 7.8% mismatched GaSb/GaAs interface.1 The challenge is therefore to reduce the threading dislocation density in the active region without a very thick metamorphic buffer or dislocation bending layers.

01 Jan 2012
TL;DR: In this paper, the authors proposed a method to solve the problem of finding the minimum number of nodes in a set of nodes for each node in order to find the minimum node in the set.
Abstract: NdPd0.85Sb2 ,t etragonal, P4/nmm (no. 129), a =4 .4098(3) A, c =9 .6907(9) A,V =1 88.4 A 3 , Z =2 , R gt (F) =0 .0369, wRref(F) =0 .0383, T =2 95 K.

Journal ArticleDOI
TL;DR: In this article, wave propagation of elastic wave in cubic scandium antimonide semiconductor was investigated and the second and third order elastic constants have been computed for the evaluation of above said ultrasonic properties.
Abstract: In this paper analysis of wave propagation of elastic wave in scandium antimonide semiconductor was investigated. In scandium antimonide semiconductor, NaCl structure was found. Ultrasonic properties like ultrasonic attenuation, sound velocities, acoustic coupling constants, and thermal relaxation time have been investigated in cubic scandium antimonide semiconductor. Second and third order elastic constant have been computed for the evaluation of above said ultrasonic properties. Second and third elastic constant was studied at the various temperatures. Longitudinal and shear velocity was calculated by using the elastic constant. Longitudinal and shear velocity increase with increase the temperature. Ultrasonic attenuation either from longitudinal or shear wave propagation in cubic materials increase with increase the temperature.