Photoresponse characteristics of InAs/GaAs self-assembled quantum-dot infrared photodetectors in a wide spectral region from the mid- to far-infrared are reported. Clear polarization behaviors with dominant P-polarized response mid-infrared and strong S-response far shown. These can be qualitatively understood view shape large in-plane diameter small height growth direction. With set three samples, effects number electrons per dot on spectra investigated.

The authors describe the noise characterization of a mid-wavelength-infrared (MWIR) photodiode based on indium arsenide and gallium antimonide (InAs/GaSb) superlattice (SL), addressing influence different passivation layers applied to surface device. MWIR InAs/GaSb SL design structure is p-i-n configuration grown by molecular beam epitaxy (001) n-GaSb substrate. SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -passivated photodiodes...

We report on the growth and opto-electronic characterization of type-II InAs/GaSb superlattice (SL) mid-wavelength infrared pin photodetector grown a GaAs substrate. AlSb interfacial misfit array was employed at buffer/GaSb epilayer interface to reduce dislocation density SL structure lattice mismatched Optical electrical performance this sample (SL-GaAs) were then compared with reference same GaSb substrate (SL-GaSb). At 80 K, dark current detectivity values photodetectors recorded as 5.40...

Abstract Optical anisotropy of the layer semiconductor GaSe has been studied by photoluminescence (PL) and Fourier Transform Infrared Spectroscopy (FTIR). The PL spectra are dominated two closely positioned emission bands resulting from free exciton bound connected direct band edge GaSe. Photoluminescence transmission crystals have measured for cases in which propagation vector k is perpendicular (k ⟂ c) parallel to c‐axis // c). Peak position onset found be significantly different these...

High-performance and lightweight laminated hybrid composites were fabricated by using epoxy-impregnated carbon, Kevlar fabrics. Carbon–Kevlar, carbon–hybrid, carbon–Kevlar–hybrid, Kevlar–hybrid fabric epoxy matrix with 12 layers synthesised vacuum bag method. Tensile three-point bending tests used to determine the modulus of elasticity, % elongation, tensile strength, moment strength composites. The highest observed from carbon–Kevlar–epoxy composite, while lowest values carbon–hybrid–epoxy...

We report on experimental results dual-band high responsivity InGaAs/InP quantum well photodetectors covering both near and mid-infrared spectral regions. The detection relies intersubband transitions. With changing width bound-to-bound bound-to-continuum have been demonstrated, thus determining the optimal design parameters for this materials system. infrared is via usual interband absorption. observed values at applied voltages are due to combined effects of low excited-electron capture...

Using the variational methods, we have calculated binding energies of lowest donor states, 1s and 2p±, in wurtzite InGaN/GaN staggered quantum wells. The narrow wells are larger magnitude than values bulk GaN due to confinement effects. However, decrease sharply wider because weakening strong built-in electric field inside well. donors placed at opposite edges well quite different as forms an asymmetric, triangular potential oscillator strength possible transitions between states is then...

Abstract Effects of the magnetic field on nonlinear optical properties at THz range in GaAs/AlGaAs quantum wells doped with donor atoms are investigated. Expressions for third‐order susceptibilities obtained through solution density matrix equations motion within rotating wave approximation. Donor binding energies calculated variationally by means an iterative shooting algorithm. Magnetic has strong effect susceptibility: it removes degeneracy 2 p ± impurity states and increases absolute...

We report on the direct observation of polarons in $\mathrm{In}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ self-assembled quantum dots (QD) populated by few electrons. The are strongly coupled modes QD phonons and electron intersublevel transitions. degree coupling is varied a systematic way with set samples having spacing changing from larger to smaller than longitudinal-optical-phonon energy. signature evidenced clearly large $(12--20\phantom{\rule{0.3em}{0ex}}\mathrm{meV})$ anticrossing for both...

Resonant tunneling through a self-assembled InAs quantum dot (QD) layer using new design is reported: The QD surrounded by undoped GaAs barriers clad two GaInNAs∕GaAs short period superlattice regions which serve as injector and collector of electrons. Clear observation three- to zero-dimensional resonant presented in electrophotoluminescence measurement results, supported with current–voltage capacitance–voltage characteristics.

The variation of barrier height with the band gap in metal/heterojunction systems is related to how Fermi level position varies respect edges. If pinned by interface states its movement will also correspond neutrality at interface. Metal/Si1−xGex/Si heterostructures (0⩽x⩽0.24) for both n- and p-type substrates were studied understand relation between Schottky barrier, movement, variations. It was shown that a correlation exists band-offset values ΔEc ΔEv. For n-type substrate, measured...

Effects of the postgrowth rapid thermal annealing on device properties a multilayer InAs∕GaAs quantum dot infrared photodetector are investigated. Clear shift in spectral photoresponse toward smaller energy region with increasing temperatures is shown. Polarization behaviors peaks presented.

GaAs/AlGaAs quantum wells doped with donor atoms are investigated for nonlinear optical applications in the THz range. The electronic properties of obtained numerically by applying an iterative shooting algorithm. Donor binding energies computed through evaluation variational wavefunctions. solution density matrix equations motion non-interacting two-level within rotating wave approximation is used to formulate third-order nonlinearities. Transitions between 1s and 2p± impurity states...

Abstract MgSe/CdSe/ZnCdMgSe step quantum well structures and coupled under an applied electric field have been investigated for the process of second harmonic generation (SHG) with double‐resonant condition. The structural parameters wells having equally spaced three consecutive energy levels within conduction band determined by solving Schrödinger equation. It is shown that level separation can be continuously tuned between 214 472 meV changing thickness material composition layers. product...

We report on the opto-electronic characterization of an InAs/GaSb superlattice (SL) midwave infrared p–i–n photodetector structure (pin-SL) in comparison with same no intentional doping (i-SL). Both structures were grown n-GaSb substrate using molecular beam epitaxy. The nominally undoped (i-SL) presented like behavior and showed a photovoltaic mode photoresponse due to residual native defects this material system. For ∼77 K operation, 0.76 0.11 A W–1 responsivity values obtained at 4 μm...

Intersubband transition energies and absorption lineshape in staggered InGaN/GaN quantum wells surrounded by GaN barriers are computed as functions of structural parameters such well width, In concentrations, the doping level well. Schrödinger Poisson equations solved self-consistently taking free bound surface charge concentrations into account. Many-body effects, namely, depolarization excitonic shifts also included calculations. Results for energies, oscillator strength, up to nonlinear...

Nanostructures made of semiconductors, such as quantum wells and dots (QD), are well known, some have been incorporated in practical devices. Here we focus on novel structures QDs related devices for terahertz (THz) generation. Their potential advantages, low threshold current density, high characteristic temperature, increased differential gain, etc, make promising candidates light emitting applications the THz region. Our idea using resonant tunneling through is presented, initial results...

We have calculated the binding energies of donor states, 1s and 2p?, with respect to lowest sub-band energy in a double quantum well composed wurtzite InGaN staggered wells GaN barriers. All wavefunctions were by applying variational methods. found that donors placed right are larger independent middle barrier width up 40 ?. This is because strong built-in electric field which brings more confinement well. The be functions position system consequence large asymmetry introduced field.

Physical systems with topological properties are robust against disorder. However, implementing them in integrated photonic devices is challenging because of the various fabrication imperfections and/or limitations that affect spectral response their building blocks. One such feature strong backscattering due to surface wall roughness waveguides, which can flip propagating modes counterpropagating and destroy desired behavior. Here, we report a study on modeling, designing testing an...