Showing papers on "Antimonide published in 2004"

Long-Wavelength Infrared Semiconductor Lasers

Abstract: Preface Acknowledgments Contributors 1 Coherent Sources in the Long-Wavelength Infrared Spectrum (Hong K Choi) 11 Introduction 12 Synopsis of Long-Wavelength Coherent Sources 13 Scope of Book 2 2- m Wavelength Lasers Employing InP-based Strained-Layer Quantum Wells (Manabu Mitsuhara and Mamoru Oishi) 21 Introduction 22 Material Properties of InGaAsP 23 Design Consideration of MQW Active Region 24 Growth and Characterization of Strained-InGaAs Quantum Wells 25 Lasing Characteristics of 2- m wavelength InGaAs-MQW Lasers 26 Conclusions and Future Prospects 3 Antimonide Mid-IR Lasers (LJ Olafsen, et al) 31 Introduction 32 Antimonide III-V Material System 33 Antimonide Lasers Emitting in the 2 m < lambda < 3 m Range 34 Antimonide Lasers Emitting in the lambda 3 m Range 35 Challenges and Issues 36 Conclusions 4 Lead-Chalcogenide-based Mid-Infrared Diode Lasers (Uwe Peter Schieal, et al) 41 Introduction 42 Homostructure Lasers 43 Double-Heterostructure Lasers 44 Quantum-Well Lasers 45 DFB and DBR Lasers 46 IV-VI Epitaxy on BaF2 and Silicon 47 Conclusion 5 InP and GaAs-Based Quantum Cascade Lasers (Jerome Faist and Carco Sirtori) 51 Introduction 52 Quantum Cascade Laser Fundamentals 53 Fundamentals of the Three-Quantum-Well Active-Region Device 54 Waveguide and Technology 55 High-Power, Room-Temperature Operation of Three-Quantum-Well Active Region Designs 56 GaAs-Based QC Lasers 57 Role of the Conduction-Band Discontinuity 58 Spectral Characteristics of QC Lasers 59 Distributed Feedback Quantum Cascade Lasers 510 Microsctructured QC Lasers 511 Outlook on Active Region Designs and Conclusions 6 Widely Tunable Far-Infrared Hot-Hole Semiconductor Lasers (Erik Brundermann) 61 Introduction 62 Hot-Hole Laser Model 63 Laser Material Fabrication 64 Technology 65 Laser Emission 66 Future Trends 67 Summary 7 Continous THz generation with Optical Heterodyning (J C Pearson, et al) 71 Introduction 72 Requirements for Photomixing Systems 73 Design Trade-offs for Photomixers 74 Antenna Design 75 Applications 76 Summary Index

Correlating growth conditions with photoluminescence and lasing properties of mid-IR antimonide type II “W” structures

Abstract: We explored the evolution of the photoluminescence (PL) properties versus molecular beam epitaxy growth conditions for a series of type II “W” quantum well [InAs/GaInSb/InAs/AlAsSb] structures. The highest PL intensities are obtained when the quantum wells are grown in a temperature range between 487 and 507 °C. Cross-sectional scanning tunneling microscopy was used to explain the temperature evolution of the PL. AlAs clustering within the AlAsSb barrier was observed at low growth temperature. The PL intensity decrease at high temperature was related to In clustering in the GaInSb layer. Laser structures grown at both 425 and 500 °C displayed lower lasing thresholds, lower internal losses, and longer Shockley–Read lifetimes than any similar structures grown previously at NRL. A thicker optical cladding layer of 3.5 μm suppressed mode leakage into the substrate and reduced the internal loss to 2.1 cm−1 at 78 K.

Materials Growth for InAs High Electron Mobility Transistors and Circuits

Abstract: High electron mobility transistors (HEMTs) with InAs channels and antimonide barriers were grown by molecular beam epitaxy. Both Si and Te were successfully employed as n-type dopants. Sheet resistances of 90–150 Ω/□ were routinely achieved on a variety of heterostructures with nonuniformities as low as 1.5% across a 75 mm wafer. X-ray diffraction measurements show that the InAs channels are in tension, coherently strained to the Al(Ga)Sb buffer layers. Atomic force microscopy measurements demonstrate that the surfaces are relatively smooth, with rms roughness of 8–26 A over a 5×5 μm2 area. These results demonstrate that the growth of InAs HEMTs has progressed to the point that the fabrication of circuits should be feasible.

Planar Nets of Ti Atoms Comprising Squares and Rhombs in the New Binary Antimonide Ti2Sb

Abstract: The new binary antimonide Ti(2)Sb was found to crystallize in a distorted variant of the La(2)Sb type, which contains a square planar La net with short La-La bonds. In the Ti(2)Sb structure, the corresponding Ti net is deformed to squares and rhombs in order to enhance Ti-Ti bonding, as proven by single-crystal X-ray investigation in combination with the real-space pair distribution function technique utilizing both X-ray and neutron powder diffraction data. Electronic structure calculations revealed a lowering of the total energy caused by the disorder, the major driving force being strengthened Ti-Ti interactions along the diagonal of the Ti(4) rhombs.

Optimizing indium aluminum antimonide LEDs and photodiodes for gas sensing applications

Abstract: We have developed a range of un-cooled mid-IR LEDs and photodiodes for IR gas sensing applications. Varying the composition of MBE grown Indium Aluminium Antimonide (In (1-x) Al x Sb) epi-layers on GaAs allows us to engineer the emission/detection wavelength for a particular gas up to λ max ≈6μm. The relatively high series resistance, LED drive requirements, and the non-optimised impedance matching of the un-biased photodiodes restricts the market for these components. Sub-dividing single element devices into N smaller devices connected in series enable the LED current and voltage requirements to be tailored to match the source, and improves the photodiode impedance matching. We report the development of the necessary growth and photolithography technologies for series-connecting InAlSb diodes on GaAs substrates. We include results from multi-element Co 2 (Al(x)=4.5%) and CH 4 (Al(x)=8.5%) sensing LEDs and photodiodes. These impedance matched LEDs represent a 9-fold improvement in the wall-plug efficiency compared with single element LEDs with the same light output. The impedance of the multi-element photodiodes is increased significantly with respect to the series resistance, which gives up to a 5-fold improvement in sensitivity since the noise contributions from the external amplifier and series resistance are minimised. These advances have greatly improved the suitability of these components for gas sensing, and further improvements in the performance are expected through optimisation of the epi-layer design and the device geometry.

Antimonide semiconductor saturable absorber for 1.5 [micro sign]m

Abstract: Self-starting continuous-wave passive modelocking of an Er:Yb:glass laser at 1535 nm is demonstrated with the first antimonide semiconductor saturable absorber mirror (SESAM) The Er:Yb:glass laser produces 20 ps pulses at 61 MHz This laser was used to characterise the nonlinear optical parameters of the metal organic vapour phase epitaxy grown SESAM

Antimonide type-II “W” lasers: growth studies and guided-mode leakage into substrate

Abstract: The lasing characteristics of mid-IR type-II “W” [InAs/GaInSb/InAs/AlAsSb] structures are found to correlate strongly with the growth conditions and low-temperature photoluminescence (PL) properties. The highest PL intensities and narrowest PL lines are obtained when the wafers are grown at ≈480–510°C with mixed interface bonds. A number of structures grown at a non-optimal lower temperature (≈425°C) nonetheless yielded lower lasing thresholds, lower internal losses, and longer Shockley-Read lifetimes than any grown previously on the present Riber 32P MBE system. All of the laser spectra display regularly-spaced multiple peaks that are consistent with periodic modulation of the cavity loss due to mode-leakage into the GaSb substrate.

Design and fabrication of 6.1-Å family semiconductor devices using semi-insulating A1Sb substrate

Abstract: For the first time, an aluminum antimonide (AlSb) single crystal substrate is utilized to lattice-match to overlying semiconductor layers. The AlSb substrate establishes a new design and fabrication approach to construct high-speed, low-power electronic devices while establishing inter-device isolation. Such lattice matching between the substrate and overlying semiconductor layers minimizes the formation of defects, such as threaded dislocations, which can decrease the production yield and operational life-time of 6.1-Å family heterostructure devices.

MOVPE growth of long wavelength AlGaAsSb/InP Bragg mirrors

Abstract: Monolithic distributed Bragg reflectors (DBRs) consisting of AlGaAsSb/InP quarter-wave multilayer were grown by metal-organic vapour-phase epitaxy (MOVPE) on InP substrates. The quality of antimonide MOVPE grown material has been optimised to achieve highly reflective, defect-free, DBR stacks. With 21 AlGaAsSb/InP periods, reflectivity up to 97% at 1.59 µm was measured.

Interband cascade lasers grown on GaAs substrates lasing at 4 microns

Abstract: Antimonide-based type II interband cascade lasers grown on GaAs substrates have been demonstrated at emission wavelengths longer than 4μm at temperatures up to 270K in pulsed-mode operation. Investigations by transmission electron microscopy, atomic force microscopy and x-ray diffraction are presented and discussed to gain insights into material issues such as defects and dislocations associated with device performance.

Native defect compensation in III-antimonide bulk substrates

Abstract: As-grown, undoped III-antimonide bulk substrates contain high concentration of native defects resulting in high residual carrier density. In this paper, we have demonstrated that native defects can be compensated in bulk substrates of GaSb, InSb, and Ga/sub 1-x/In/sub x/Sb via impurity doping and low temperature growth from nonstoichiometric melts and solutions. Decrease in residual carrier concentration up to one order of magnitude at 300 K and three orders of magnitude at 77 K have been achieved.

InAs/InAsP composite channels for antimonide-based field-effect transistors

Abstract: We report the growth and transport characteristics of stepped InAs/InAs1−xPx quantum wells with AlSb barriers. Electron mobilities and carrier concentrations in these composite stepped quantum wells were studied as a function of growth temperature and phosphorus content. For InAs1−xPx grown at 430 °C substrate temperature (nominal x=0.2), a high 22 500 cm2/V s electron mobility was observed, while 7100 cm2/V s mobility was observed in a single strained InAs1−xPx quantum well layer. Heterostructure field-effect transistors fabricated using the composite quantum wells exhibited increased breakdown voltage and a 14:1 reduction in source-drain dc conduction when compared to a similar InAs-channel device.

Gallium arsenide antimonide (GaAsSB)/indium phosphide (InP) heterojunction bipolar transistor (HBT) having reduced tunneling probability

Abstract: A heterojunction bipolar transistor (HBT), comprises a collector formed over a substrate, a base formed over the collector, an emitter formed over the base, and a tunneling suppression layer between the collector and the base, the tunneling suppression layer fabricated from a material that is different from a material of the base and that has an electron affinity equal to or greater than an electron affinity of the material of the base.

Fe-Co-As およびFe-Co-Sb 合金の1150°C における相関係と成分活量

Abstract: Arsenic and antimony activities in the Fe-Co-As and Fe-Co-Sb ternary systems were measured at 1150°C by an isothermal isopiestic method to obtain fundamental information about the behavior of arsenic and antimony in processing intermediate products and cobalt arsenide or antimonide ores. Phase relations between the solid solution and liquid phases in a region of dilute arsenic or antimony in these systems were also determined at 1150°C with a quenching technique. The isoactivity lines of arsenic in the homogeneous liquid phase were almost parallel to the Co-Fe axis of the Fe-Co-As ternary composition diagram, while those of antimony represented a negative gradient due to stronger chemical affinity of antimony to cobalt as compared to iron. The iron and cobalt activities in these ternary systems were derived from the measured arsenic or antimony activity and the determined phase relations. The Redlich-Kister-Muggianu polynomial formula was successfully applied to express the activities as a function of alloy compositions. Based on the obtained data, the total pressures of arsenic and antimony gas species were evaluated to discuss the possibility to recover or eliminate arsenic and antimony from the alloys by means of volatilization.

High resistivity aluminum antimonide radiation and alpha-particle detector

Abstract: Bulk Aluminum Antimonide (AlSb)-based single crystal materials have been prepared for use as ambient (room) temperature X-ray and Gamma-ray radiation and alpha-particle detection.

Recombination parameters for antimonide-based semiconductors using the radio frequency photoreflectance technique

Abstract: Radio-frequency (RF) photoreflectance measurements and one-dimensional device simulations have been used to evaluate bulk and surface recombination parameters in doubly capped, 0.50–0.59-eV, p-type InGaAsSb epitaxial materials. The InGaAsSb lifetime structures with variable active-layer thicknesses are used to extract the surface recombination velocity (SRV), while samples with different active-layer doping concentrations have been used to determine the Auger and radiative recombination coefficients. The RF photoreflectance measurements and analysis are compatible with a radiative recombination coefficient (B) of approximately 3×10−11 cm3/s, Auger coefficient (C) of 1×10−28 cm6/s, and SRV of ∼103 cm/s or lower for 0.50–0.59 eV, doubly capped, p-type InGaAsSb epitaxial layers.

Characterization of InGaSb detectors for 1.0- to 2.4-μm applications

Abstract: Near infrared detectors in the 1 to 2.4 μm spectral range are important for many applications such as atmospheric remote sensing, where several species have strong absorption spectra in that range. Antimonide-based III-V compound semiconductor materials are good candidates for developing detectors in that spectral range. Electrical and optical characteristics of In 1-x Ga x Sb p-n photodetectors at different temperatures are presented. The devices were fabricated either on bulk InGaSb substrates by zinc diffusion or InGaSb epitaxial layers grown on GaSb substrates by organo-metallic vapor phase epitaxy (OMVPE). Variable area devices were fabricated. Current-voltage measurements indicated higher dark current in InGaSb devices grown on GaSb substrate, due to defects generated by the lattice-mismatch. Spectral response measurements were obtained in the 1 to 2.4 μm wavelength range at different temperatures. At room temperature, the cut-off wavelengths were observed at 2.3 and 2.1 μm for InGaSb devices grown on GaSb and for devices fabricated on bulk InGaSb substrates respectively. Reducing the operating temperature shifts the cut-off wavelength to shorter values and increases the responsivity. Noise calculations indicated a room temperature detectivities of 3.3x10 10 and 5.5x10 10 cmHz 1/2 /W at 2 μm for the GaSb and InGaSb respectively. Detectivity variation with wavelength will be presented and compared to the background limited performance.

Antimony Based III-V Thermophotovoltaic Devices

Abstract: Antimony-based III-V thermophotovoltaic (TPV) cells are attractive converters for systems with low radiator temperature around 1100 to 1700 K, since these cells potentially can be spectrally matched to the thermal source. Cells under development include GaSb and the lattice-matched GaInAsSb/GaSb and InPAsSb/InAs quaternary systems. GaSb cell technology is the most mature, owing in part to the relative ease in preparation of the binary alloy compared to quaternary GaInAsSb and InPAsSb alloys. Device performance of 0.7-eV GaSb cells exceeds 90% of the practical limit. GaInAsSb TPV cells have been the primary focus of recent research, and cells with energy gap E{sub g} ranging from {approx}0.6 to 0.49 eV have been demonstrated. Quantum efficiency and fill factor approach theoretical limits. Open-circuit voltage factor is as high as 87% of the practical limit for the higher-E{sub g} cells, but degrades to below 80% with decreasing E{sub g} of the alloy, which might be due to Auger recombination. InPAsSb cells are the least studied, and a cell with E{sub g} = 0.45-eV has extended spectral response out to 4.3 {micro}m. This paper briefly reviews the main contributions that have been made for antimonide-based TPV cells, and suggests additional studies for further performance enhancements.

Atomically flat III-antimonide epilayers grown using liquid phase epitaxy

Abstract: A novel process has been developed which allows the growth of device grade ultra-smooth epitaxial layers of antimonide based III-V compounds with a controlled thickness using liquid phase epitaxy (LPE). GaSb epilayers (with thickness in the range of 20-50 /spl mu/m) on GaSb single crystalline substrates have been grown with a root mean square surface roughness of less than 1 nm over an area of 5/spl conint/ /spl larr/ 5 /spl mu/m.

High temperature laser diode

Abstract: A semiconductor laser structure having confinement layers to confine electrons to an active region (quantum wells) and having separate antimonide-based cladding layers to provide additional electron confinement and photon confinement is suited to high temperature operation. The structure is suitable for lasing across telecommunications wavelengths from 980 nm to 1.55 µm (microns) . The cladding layer uses AlAsSb which can be lattice-matched to InP and can be used to achieve large conduction band offsets. It is very useful for coolerless (without thermo-electric cooler) operation.

MBE grown alkali antimonide photocathodes

Abstract: A photocathode manufacturing intermediary article (24) includes a substrate layer (26), and an active layer (20) that is carried by the substrate layer (26). The active layer (20) includes photoemissive alkali antimonide material that is epitaxially grown on the substrate (26).