Showing papers on "Antimonide published in 2011"
01 Dec 2011
TL;DR: In this article, the authors demonstrate hetero tunnel FET (TFET) with record high drive currents (I ON ) of 190µA/µm and 100 µA/m at V DS = 0.75V and 0.3V, respectively (L G = 150nm).
Abstract: Type II arsenide/antimonide compound semiconductor with highly staggered GaAs 0.35 Sb 0.65 /In 0.7 Ga 0.3 As hetero-junction is used to demonstrate hetero tunnel FET (TFET) with record high drive currents (I ON ) of 190µA/µm and 100µA/µm at V DS =0.75V and 0.3V, respectively (L G =150nm). In x Ga 1−x As (x=0.53, 0.7) homo-junction TFETs and GaAs 0.5 Sb 0.5 /In 0.53 Ga 0.47 As hetero TFET with moderate stagger are also fabricated with the same process flow for benchmarking. Measured and simulated TFET performance is benchmarked with 40nm strained Si MOS-FETs for 300mV logic applications.
111 citations
TL;DR: In this article, thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented, where the emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun.
Abstract: Thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun The thermal emittance is 056+/-003 mm-mrad/mm(rms) at 532 nm wavelength The results are compared with a simple photoemission model and found to be in a good agreement
61 citations
TL;DR: In this paper, thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented, using a solenoid scan technique using a high voltage dc photoemission gun.
Abstract: Thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented. The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun. The thermal emittance is 0.56±0.03 mm mrad/mm(rms) at 532 nm wavelength. The results are compared with a simple photoemission model and found to be in a good agreement.
58 citations
TL;DR: In this article, the authors demonstrate the heteroepitaxy of fully relaxed GaSb epilayers on InP(001) substrates, and the properties of the Al2O3/GaSb interface have been studied by in situ deposition of an Al 2O3 high-κ gate dielectric.
Abstract: The integration of high carrier mobility materials into future CMOS generations is presently being studied in order to increase drive current capability and to decrease power consumption in future generation CMOS devices. If III–V materials are the candidates of choice for n-type channel devices, antimonide-based semiconductors present high hole mobility and could be used for p-type channel devices. In this work we first demonstrate the heteroepitaxy of fully relaxed GaSb epilayers on InP(001) substrates. In a second part, the properties of the Al2O3/GaSb interface have been studied by in situ deposition of an Al2O3 high-κ gate dielectric. The interface is abrupt without any substantial interfacial layer, and is characterized by high conduction and valence band offsets. Finally, MOS capacitors show well-behaved C–V with relatively low Dit along the bandgap, these results point out an efficient electrical passivation of the Al2O3/GaSb interface.
39 citations
TL;DR: In this paper, the state-of-the-art performance in antimonide superlattice based long-wavelength infrared photodetectors using a complementary barrier infrared detector (CBIRD) design is reported.
22 citations
19 citations
TL;DR: In this article, a self-supported nickel antimonides/Ni architectured electrodes were prepared by solid state reaction from Ni thin film, Ni foam and Ni nanorods.
18 citations
TL;DR: The high adjustability of the crystal structure as well as properties by optimization of the chemical composition in the compounds REOZnSb provide good prospects for achieving high thermoelectric efficiency.
Abstract: An efficient route to construct a three-dimensional crystal structure is stacking of two-dimensional building blocks (2D-BBs). The crystal structures of potential thermoelectric compounds REOZnSb (RE = La, Ce, Pr, Nd) were virtually constructed from insulating [REO] and conducting [ZnSb] layers. Further optimizations performed by means of first-principles calculations show that REOZnSb should exhibit semimetal or narrow band-gap semiconductor behaviors, which is a prerequisite for high thermoelectric efficiency. The analysis of the electron localizability indicator for LaOZnSb reveals mostly covalent polar interactions between all four kinds of atoms. The electron density yields completely balanced ionic-like electronic formula La1.7+O1.2−Zn0.4+Sb0.9−. Furthermore, the samples of REOZnSb have been synthesized via solid-state reaction, and their crystal structures were confirmed by powder X-ray diffraction. The differences in cell parameters between the theoretically optimized and the experimental values are smaller than 2%. The temperature dependence of the magnetic susceptibility shows that LaOZnSb is diamagnetic above 40 K, whereas CeOZnSb, PrOZnSb and NdOZnSb are Curie–Weiss-type paramagnets. Electrical conductivity and Seebeck effect measurements indicate that REOZnSb are p-type semiconductors. A considerably high Seebeck coefficient and low thermal conductivity were obtained for pure LaOZnSb, but its low electrical conductivity leads to a small ZT. The high adjustability of the crystal structure as well as properties by optimization of the chemical composition in the compounds REOZnSb provide good prospects for achieving high thermoelectric efficiency.
17 citations
TL;DR: In this article, enhancement-mode (e-mode) antimonide MOSFETs were demonstrated by integrating a composite high-κ gate stack (3 nm Al2O3 -1 nm GaSb) with an ultrathin InAs0.7Sb0.3 quantum well (7.5 nm).
Abstract: This letter demonstrates, for the first time, enhancement-mode (e-mode) antimonide MOSFETs by integrating a composite high-κ gate stack (3 nm Al2O3 -1 nm GaSb) with an ultrathin InAs0.7Sb0.3 quantum well (7.5 nm). The MOSFET exhibits record high electron drift mobility of 5200 cm2/V · s at carrier density (Ns) of 1.8 × 1012 cm-2, subthreshold slope of 150 mV/dec, ION/IOFF ratio of ~4000× within a voltage window of ~1 V, high ION of 40 μA/μm at VDS of 0.5 V for a 5-μm gate length (LG) device. The device exhibits excellent pinchoff in the output characteristics with no evidence of impact ionization enabled by enhanced quantization and e-mode operation. RF characterization allows extraction of the intrinsic device metrics (Cgs, Cgd, gm, veff and ft) and the parasitic resistive and capacitive elements limiting the short-channel device performance.
17 citations
TL;DR: The interaction of antimony with the nickel-zirconia anode in solid oxide fuel cells (SOFCs) has been investigated in this article, where both anode-supported and electrolyte-supported button cells were performed at 700 and 800°C in synthetic coal gas containing 100-ppb to 9-ppm antimony.
13 citations
TL;DR: The Zintl phase EuGa2Sb2 was synthesized by induction melting of the elements in a sealed tantalum tube as discussed by the authors, and the structure was refined from X-ray single-crystal diffractometer data: new type, Pnma, a = 1834.7(3), b =432.25(7), c =674.8(1) pm, wR2 = 0.0377, 875 F 2, and 32 variables.
Abstract: The Zintl phase EuGa2Sb2 was synthesized by induction melting of the elements in a sealed tantalum tube. The structure was refined from X-ray single-crystal diffractometer data: new type, Pnma, a = 1834.7(3), b = 432.25(7), c = 674.8(1) pm, wR2 = 0.0377, 875 F
2, and 32 variables. The structure consists of a three-dimensional polyanionic [Ga2Sb2]2– network with Ga
2
4+
dumb-bells (252.1(1) pm Ga1–Ga2) and antimonide anions, leading to the electron-precise description Eu2+[Ga2Sb2]2−. The divalent character of europium was evident from magnetic susceptibility data and 151Eu Mossbauer spectra. The crystal chemical relationship with the structures of EuGa2As2 and BaGa2Sb2 is discussed.
TL;DR: In this paper, the antimonide-based type-II superlattices have been shown theoretically to have reduced Auger-Recombination (G-R) and suppressed band-to-band tunneling.
Abstract: Significant progress has been achieved in the antimonide-based type-II superlattices since the analysis by Smith
and Mailhiot in 1987 first pointed out their advantages for infrared detection. In the long-wavelength infrared
(LWIR), type-II InAs/Ga(In)Sb superlattices have been shown theoretically to have reduced Auger
recombination and suppressed band-to-band tunneling. Suppressed tunneling in turn allows for higher doping in
the absorber, which has led to reduced diffusion dark current. The versatility of the antimonide material system,
with the availability of three different types of band offsets, provides great flexibility in device design.
Heterostructure designs that make effective use of unipolar barriers have demonstrated strong reduction of
generation-recombination (G-R) dark current. As a result, the dark current performance of antimonide
superlattice based single element LWIR detectors is now approaching that of the state-of-the-art MCT detector.
To date, the antimonide superlattices still have relatively short carrier lifetimes; this issue needs to be resolved
before type-II superlattice infrared detectors can achieve their true potential. The antimonide material system has
relatively good mechanical robustness when compared to II-VI materials; therefore FPAs based on type-II
superlattices have potential advantages in manufacturability. Improvements in substrate quality and size, and
reliable surface leakage current suppression methods, such as those based on robust surface passivation or
effective use of unipolar barriers, could lead to high-performance large-format LWIR focal plane arrays.
Patent•
24 Oct 2011TL;DR: In this paper, the Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications, and the AlSb-based solar cell devices as disclosed herein provide direct conversion of solar energy to electrical power.
Abstract: Electronic device quality Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications. Like that of a GaAs-based solar cell devices, the AlSb-based solar cell devices as disclosed herein provides direct conversion of solar energy to electrical power.
TL;DR: In this article, the results of metal-organic epitaxy of In-and Al-containing layers and quantum well structures composing antimonide lasers devices were presented, and the results suggested a substantial influence of precursors pre-reactions on the epitaxial process.
Abstract: The antimonide laser heterostructures growth technology using MBE epitaxy is currently well-developed, while MOVPE method is still being improved. It is known that the principal problem for MOVPE is the oxygen and carbon contamination of aluminium containing waveguides and claddings. The solution would be to apply a proper aluminium precursor. In this study we present the results of metal-organic epitaxy of In- and Al-containing layers and quantum well structures composing antimonide lasers devices. Special emphasis was put on the aluminium precursor and its relation to AlGaSb and AlGaAsSb materials properties. The crystalline quality of the layers grown with two different Al precursors was compared, very good structural quality films were obtained. The results suggested a substantial influence of precursors pre-reactions on the epitaxial process. The oxygen contamination was measured by SIMS, which confirmed its dependence on the precursor choice. We also optimised the GaSb substrate thermal treatment to deposit high quality GaSb homoepitaxial layers. Quaternary InGaAsSb layers were obtained even within the predicted miscibility gap, when arsenic content reached high above 10% values. InGa(As)Sb/AlGa(As)Sb quantum wells were grown and their optical properties were characterised by photoluminescence and photoreflectance spectroscopy. Type-I quantum wells showed a fundamental optical transition in the 1.9–2.1 μm range at room temperature. The epitaxial technology of the structures was subjected to an optimisation procedure. The investigated layers and heterostructures can be considered for application in laser devices.
TL;DR: In this paper, the growth and characterization of antimonide-based compound semiconductor substrates was described and the Czochralski technique was used to grow single crystals of 4" InSb and 4" GaSb with dislocation densities of======<20/cm2 and <100/ cm2, respectively.
Abstract: In this paper we describe the growth and characterization of antimonide based compound semiconductor substrates. The
Czochralski technique has been used to grow single crystals of 4" InSb and 4" GaSb with dislocation densities of
<20/cm2 and <100/cm2, respectively. Epitaxy ready wafer surfaces have been characterized by surface microscopy and
spectroscopic ellipsometry, revealing sub-nanometer levels of surface roughness (rms) and oxide coverage in the 10-50
Angstrom range. GaSb wafers with thinner oxides (<20 Angstroms) have been developed and quality assessments made
by epitaxial growth testing. Surface morphology evaluations indicate high levels of surface quality, comparable to pretreated
variants of the same substrate type. We also illustrate current crystal growth systems and ingot forms, and
discuss the challenges associated with scaling present InSb and GaSb technologies to deliver larger substrate formats.
Patent•
09 Feb 2011
TL;DR: In this paper, an intermediate infrared antimonide laser device structure adopting DWELL was presented, where a DOT is embedded in a WELL, and the efficiency of the device was improved by increasing the number of the validity period of DWEll in the device.
Abstract: The invention discloses an intermediate infrared antimonide laser device structure adopting DWELL, namely the intermediate infrared laser structure of DWELL, wherein, a DOT is embedded in a WELL, and the efficiency of the device is improved by increasing the number of the validity period of DWELL in the device. In component of active area is reduced, and quantum dots, well width and covering layers are optimized to reduce epitaxial layer strain to the minimum. As the emission efficiency and optical gain of the quantum dots are stronger than quantum wells; the capture ability, reflectivity andoptical limiting ability of DWELL to electrons are stronger than single-layered quantum dots and multi-quantum dot structure, and the DWELL structure has higher emission efficiency. The intermediate infrared laser of the DWELL structure has both characteristics of the traditional quantum well and a quantum dot laser, and the carrier in DWELL has higher composite efficiency, thus the laser structure can work under higher temperature.
TL;DR: In this paper, the authors report growth, processing, and characterization of antimonide superlattice long-wavelength infrared photodetectors based on the complementary barrier infrared detector (CBIRD) design.
TL;DR: In this paper, a Fabry-Perot single spatial mode antimonide-based type-I quantum-well ridge waveguide semiconductor diode laser operating at 3.0-3.2 µm wavelength in continuous mode up to 333 K was demonstrated.
Abstract: We have demonstrated Fabry–Perot single spatial mode antimonide-based type-I quantum-well ridge waveguide semiconductor diode lasers operating at 3.0–3.2 µm wavelength in continuous mode up to 333 K. Internal optical loss in narrow ridge devices was significantly reduced by using thick Si3N4 dielectric films for planarization. The fabricated lasers operate in CW mode at room temperature with output powers exceeding 5 mW and have power consumption of less than 0.2 W at the output power of 1 mW, which is the power level needed in many gas sensing applications.
TL;DR: In this article, the surface morphologies for In0.27Ga0.73Sb regrown on InAs exhibit smooth surfaces with similar root-mean-square roughness to the as-grown InAs, which in turn is similar to the roughness of the AlGaSb buffer layer below it.
Abstract: We have investigated regrowth of p + InGaSb on AlGaSb and on thin InAs etch-stop layers after atomic hydrogen cleaning (AHC) surface treatments. Following certain cleaning conditions, the surface morphologies for In0.27Ga0.73Sb regrown on InAs exhibit smooth surfaces with similar root-mean-square (rms) roughness to the as-grown InAs, which in turn is similar to the roughness of the AlGaSb buffer layer below it. In addition, hole mobilities for InGaSb regrown on AHC InAs approach the highest mobilities reported to date for any p + III–V semiconductors. A wide range of AHC conditions including substrate temperatures from 280°C to 370°C and exposure durations between 5 min and 30 min result in smooth InGaSb films with low resistivity.
TL;DR: In this paper, the structural properties of 3D transition metal antimonide compounds ATM 2 Sb 2 were investigated by first-principles calculations, and it was shown that all the stable compounds in the CaBe 2 Ge 2 -type structure have strong interlayer interactions.
20 Sep 2011
TL;DR: In this paper, the synthesis and single-crystal X-ray structure determination of the new antimonide oxide, Ba5Cd2Sb4O2, were reported.
Abstract: Synthesis and single-crystal X-ray structure determination of the new antimonide oxide, Ba5Cd2Sb4O2 are reported. Ba5Cd2Sb4O2 crystallizes in the monoclinic space group C2/m (No. 12) with unit cell parameters: a = 17.247(7) A, b = 4.9279(18) A, c = 12.240(5) A, and β = 132.558(4)°; Z = 2. Its crystal structure can be described as a polyanionic [Cd2Sb4]6– sub-lattice made up of fused CdSb4 tetrahedra, stacked between puckered slabs of oxo-anions, O2–, and Ba2+ cations. This structure can also be described as a “double-salt”, i.e., a structure composed of fragments from the Zintl phase Ba3Cd2Sb4 intercalated by two BaO-like moieties. The topological similarities between the structures of these compounds are discussed.
TL;DR: In this article, the composition of MBE grown AlGaAsSb layers is investigated in the context of unintentional arsenic incorporation, and the accuracy can be increased to ± 0.52% of Al.
Abstract: The accurate determination of the chemical composition of multicomponent antimonide layers still remains difficult. The problem becomes even more complicated when group III antimonides are grown in a MBE chamber that is also used for the growth of group III arsenides. In this paper, the composition of MBE grown AlGaAsSb layers is investigated in the context of unintentional arsenic incorporation. Control of the As concentration and a determination of the AlGaSb composition are crucial for an accurate calculation of the AlGaAsSb stoichiometry. It has been found that when using diffraction measurements with an As detection limit of 0.087%, the Al content in Al0.5Ga0.5Sb is determined with an accuracy of ±1%. Taking into account the GaSb reference from secondary ion mass spectrometry, the accuracy can be increased to ±0.52% of Al. The Al/Ga ratio determined for AlGaSb layers is further used for the calculation of the As content in AlGaAsSb alloys grown under the same technological conditions as the ternary l...
25 May 2011
TL;DR: In this article, an epitaxial process is used for the growth of antimonide active regions on GaAs/AlGaAs distributed Bragg Reflectors (DBRs) resulting in 2 μm VECSELs.
Abstract: We demonstrate a novel epitaxial process for the growth of low-dislocation density GaSb on GaAs. The
growth mode involves the formation of large arrays of periodic 90° misfit dislocations at the interface
between the two binary alloys which results in a completely strain relieved III-Sb epi-layer without the
need for thick buffer layers. This epitaxial process is used for the growth of antimonide active regions
directly on GaAs/AlGaAs distributed Bragg Reflectors (DBRs) resulting in 2 μm VECSELs on GaAs
substrates.
TL;DR: A new CaCu5 related antimonide, CePt5Sb, has been identified in this article, which undergoes a structural phase transition at about 80 K according to room and low-temperature X-ray and neutron di...
Abstract: A new CaCu5 related antimonide, CePt5Sb, has been identified. This ternary compound undergoes a structural phase transition at about 80 K according to room- and low-temperature X-ray and neutron di...
19 Jun 2011
TL;DR: In this article, the p-B-n (p-type, barrier, n-type) structure of thermophotovoltaics (TPVs) was characterized using InAs 0.91 Sb 0.09 lattice matched to GaSb.
Abstract: Thermophotovoltaics (TPVs) have attracted interest due to their ability to harvest infrared radiation and produce usable energy. The focus of this research is the characterization of novel TPV cell designs which employ a barrier layer in the pn junction, creating a p-B-n (p-type, barrier, n-type) structure. First suggested for use with photodetectors, the monovalent barrier is designed to block only one carrier; it exists in either the valence band or conduction band but not both. This monovalent band is accomplished by careful selection of a wide bandgap material in place of, or in addition to, the intrinsic layer. The use of a barrier layer enables these p-B-n cells to operate at longer wavelengths, higher efficiencies, and higher operating temperatures. p-B-n designs utilizing InAs 0.91 Sb 0.09 lattice matched to GaSb were examined. Barrier and absorber materials were researched and simulations were performed to determine optimal band alignments as well as to perform an initial optimization of the design.
TL;DR: In this paper, the nearly lattice-matched antimonide material system, consisting of InAs, GaSb, AlSb and their alloys, allows for the construction of superlattice heterostructures.
Abstract: The nearly lattice-matched InAs/GaSb/AlSb (antimonide) material system offers tremendous
flexibility in realizing high-performance infrared detectors Antimonide-based superlattice (SL)
detectors can be tailor-made to have cutoff wavelengths ranging from the short wave infrared
(SWIR) to the very long wave infrared (VLWIR) SL detectors are predicted to have suppressed
Auger recombination rates and low interband tunneling, resulting in the suppressed dark currents
Moreover, the nearly lattice-matched antimonide material system, consisting of InAs, GaSb, AlSb
and their alloys, allows for the construction of superlattice heterostructures 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 our recent efforts in achieving state-of-the-art performance in
antimonide superlattice based infrared photodetectors
Patent•
03 Mar 2011
TL;DR: In this paper, a method for making films, nanostructures and nanowires in templates and on substrates, including but not limited to metal-semiconductor nanostructure, was described.
Abstract: This invention pertains generally to compositions and a method for making films, nanostructures and nanowires in templates and on substrates, including but not limited to metal-semiconductor nanostructures and semiconductor nanostructures on semiconductor substrates, and a device having the same. Particularly described are methods for making cobalt antimonide nanostructures on gold and Co—Sb substrates.
03 Feb 2011-Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena
TL;DR: In this paper, the pN heterojunction is composed of a 30 nm thick p-type In0.27Ga0.73Sb alloy and a 130 nm thick In 0.41Sb0.59 n-layer.
Abstract: High frequency pN heterojunction diodes with cutoff frequencies over 1 THz have been fabricated using narrow bandgap high-mobility semiconductors. The pN heterojunction is composed of a 30 nm thick p-type In0.27Ga0.73Sb alloy and a 130 nm thick In0.69Al0.31As0.41Sb0.59 n-layer. A high-mobility n-type InAs0.66Sb0.34 contact layer is used to connect the mesa diode to a metal Ohmic contact. These alloys have a lattice constant a0=6.2 A and are grown on semi-insulating GaAs, a0=5.65 A, using a buffer consisting of 1 μm of In0.21Ga0.19Al0.6Sb with a0=6.2 A and 0.5 μm of Ga0.35Al0.65Sb with a0=6.12 A.