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This paper presents a theoretical analysis of an nBp infrared barrier detector's performance intended to operate at a room temperature (300 K) based on AIIIBV materials—In1-xGaxAsySb1−y quaternary compound—lattice-matched to the GaSb substrate with a p-n heterojunction ternary Al1−xGaxSb barrier. Numerical simulations were performed using a commercial Crosslight Software—package APSYS. The band structure of the nBp detector and the electric field distribution for the p-n heterojunction with and without a potential barrier were determined. The influence of the barrier-doping level on the detector parameters was analyzed. It was shown that Shockley-Read-Hall (SRH) recombination plays a decisive role in carrier transport for lifetimes shorter than 100 ns. The influence of the absorber/barrier thickness on the detector's dark current density and photocurrent was investigated. It was shown that valence band offset does not influence the device's performance. The quantum efficiency reaches its maximum value for an absorber's thickness of ~3 μm. The performed simulations confirmed the possibility of the detector's fabrication exhibiting high performance at room temperature based on quaternary compounds of AIIIBV materials for the short wavelength infrared range. [ABSTRACT FROM AUTHOR]

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Thermophotovoltaic conversion using heat to generate electricity in photovoltaic cells based on the detraction of thermal radiation suffers from many engineering challenges. The focus of this paper is to study the nanostructure of AlGaAsSb for thermophotovoltaic energy conversion using lattice-matched heterostructures of GaSb-based materials in order to overcome the current challenges. The XAFS spectroscopy technique was used to analyze electronic structures and optical properties of GaSb, (Al, In) GaSbAs. The XAFS spectroscopy analysis showed a powerful decay at peak intensity that reveals to be related to a loss in Sb amount and light As atoms replaced in Sb atoms by 25%. Moreover, it was found that Al/In doped samples have highly symmetric data features (same atomic species substitution). The narrow direct bandgap energy, Eg of Al0.125Ga0.875Sb0.75As0.25 material raised (0.4–0.6 eV) compared to conventional photovoltaic cell bandgap energy (which is generally less than 0.4 eV) with weak absorption coefficients. The thermoelectric properties of AlGaAsSb computed via Botlztrap code showed that the electrons made up the majority of the charge carriers in AlGaAsSb. This nanostructure material exhibited a higher and acceptable figure of merit and demonstrated a promising thermoelectric material for solar thermophotovoltaic applications. [ABSTRACT FROM AUTHOR]

We provide an overview of our progress on the development of linear mode avalanche photodiodes (LmAPDs) on InP substrates using antimony (Sb)-based multipliers for short-wavelength infrared (SWIR) spectral region. We identify the key figures of merit of LmAPDs to provide higher sensitivity and speed for applications like light detection and ranging (LiDAR) and remote sensing. We discuss the design of separate absorption, charge, and multiplication (SACM) APDs that are used for narrow gap absorption. We summarize our results on the impact ionization, multiplication gain, dark current, and excess noise of AlGaAsSb and AlInAsSb multipliers lattice-matched to InP substrates. Finally, we identify the key technical challenges associated with the development of SACM APDs on InP substrates. [ABSTRACT FROM AUTHOR]

Thermophotovoltaic conversion using heat to generate electricity in photovoltaic cells based on the detraction of thermal radiation suffers from many engineering challenges. The focus of this paper is to study the nanostructure of AlGaAsSb for thermophotovoltaic energy conversion using lattice-matched heterostructures of GaSb-based materials in order to overcome the current challenges. The XAFS spectroscopy technique was used to analyze electronic structures and optical properties of GaSb, (Al, In) GaSbAs. The XAFS spectroscopy analysis showed a powerful decay at peak intensity that reveals to be related to a loss in Sb amount and light As atoms replaced in Sb atoms by 25%. Moreover, it was found that Al/In doped samples have highly symmetric data features (same atomic species substitution). The narrow direct bandgap energy, Eg of Al0.125Ga0.875Sb0.75As0.25 material raised (0.4–0.6 eV) compared to conventional photovoltaic cell bandgap energy (which is generally less than 0.4 eV) with weak absorption coefficients. The thermoelectric properties of AlGaAsSb computed via Botlztrap code showed that the electrons made up the majority of the charge carriers in AlGaAsSb. This nanostructure material exhibited a higher and acceptable figure of merit and demonstrated a promising thermoelectric material for solar thermophotovoltaic applications.

The electrical and optical properties of non-doped and Te doped 6.5 periods AlGaAsSb/AlAsSb Bragg mirrors on InP grown by MBE with different types of interfaces between ternary and quaternary layers are reported. The techniques employed were photoluminescence, refectivity and IxV measurements. The digital alloy gradient interface seems to be the best alternative to optimize conduction without significant refectivity losses.

The reflectivity of a Bragg mirror composed by materials of the antimony family (AlGaAsSb/AlAsSb), doped with tellurium, is analyzed in this work. The sample was prepared by molecular beam epitaxy (MBE) and the reflectivity was measured by Fourier Transform Infra-Red Spectroscopy (FTIR). In order to discuss the Bragg mirror properties, the experimental reflectivity is compared to a simulation of the reflectivity based on the matrix formalism.

São apresentadas as propriedades elétricas e ópticas de espelhos de Bragg com 6.5 períodos de AlGaAsSb/ AlAsSb não dopado e dopados com Te, sobre InP, crescidos por MBE com diferentes tipos de interface entre as camadas de material ternário e quaternário. As técnicas empregadas foram fotoluminescência, reflectividade e medições de IxV. A interface com liga digital em gradiente parece ser a melhor alternativa para otimizar condução elétrica sem perdas significativas da reflectividade.

Analisamos neste trabalho, a refletividade de um espelho de Bragg composto por materiais da família do antimônio (AlGaAsSb/AlAsSb) dopado com telúrio. As amostras foram preparadas através da técnica de epitaxia por feixe molecular MBE (Molecular Beam Epitaxy) e as medidas de refletividade pela técnica de espectroscopia de infravermelho por transformada de Fourier FTIR (Fourier Transform Infra- Red). Para discussão das propriedades do espelho de Bragg comparamos a refletividade obtida experimentalmente e uma simulação baseada no formalismo matricial.

GaInAsSb and AlGaAsSb alloys have been grown by organometallic vapor phase epitaxy (OMVPE) using all organometallic sources, which include tritertiarybutylaluminum, triethylgallium, trimethylindium, tertiarybutylarsine (TBAs), and trimethylantimony. Excellent control of lattice-matching both alloys to GaSb substrates is achieved with TBAs. GaInAsSb/AlGaAsSb multiple quantum well (MQW) structures grown by OMVPE exhibit strong 4K photoluminescence with full width at half maximum of 10 meV, which is comparable to values reported for quantum well (QW) structures grown by molecular beam epitaxy. Furthermore, we have grown GaInAsSb/AlGaAsSb MQW diode lasers which consist of n- and p-doped Al0.59Ga0.41As0.05Sb0.95 cladding layers, Al0.28Ga0.72As0.02Sb0.98 confining layers, and four 15 nm thick Ga0.87In0.13As0.12Sb0.88 quantum wells with 20 nm thick Al0.28Ga0.72As0.02Sb0.98 barrier layers. These lasers, emitting at 2.1 µm, have exhibited room-temperature pulsed threshold current densities as low as 1.2 kA/cm2. [ABSTRACT FROM AUTHOR]

We report the molecular beam epitaxial growth of AlGaAsSb (0.0 ≤ x ≤ 1.0) on undoped, liquid-encapsulated Czochralski, (100) oriented InAs substrates. The degree of lattice mismatch was determined by x-ray diffraction. The lattice matched materials ( y ≈ 0.08 + 0.08 x) were characterized by low temperature photoluminescence, electro-reflectance, and capacitance-voltage measurements. The experimental bandgap energies agree with earlier experimental results for AlGaSb, and also with a self-consistent first principles pseudopotential model. The capacitance-voltage measurements indicate background acceptor concentrations for the unintentionally-doped epitaxial layers of about 2 × 10 cm at x = 1.0 to 5 × 10 cm at x ≈ 0.0. [ABSTRACT FROM AUTHOR]