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Based on the generalized stochastic nonlinear Schrodinger equation, the effect of initial chirp on the broadband amplitude noise of supercontinuum generated in fiber normal dispersion regime is investigated numerically. The results show that, in the normal dispersion region, where the bandwidths of the obtained spectra are less sensitive to the initial chirp parameters of the input pulses, the nonlinear process is significantly affected by the initial chirp. An optimal input positive chirp will shorten the action time of intrapulse Raman scattering, and decrease the spectral broadband amplitude noise without bandwidth and flatness loss.

Boron-containing GaAsSb/GaAs quantum wells (QWs) with different antimony (Sb) mole fractions were grown by low-pressure metal–organic chemical vapor deposition for the first time. The effects of boron incorporation on the performance of GaAsSb/GaAs QWs are discussed. For samples with low compressive strain, injection of triethylboron can enhance the Sb content and increase the compressive strain, although boron incorporation can lead to a reduction in strain. This effect was less for strained GaAsSb/GaAs QWs, so the compressive strain of these QWs did not vary. Room-temperature photoluminescence emission at 1116 nm with a full-width at half-maximum (FWHM) value of 56 meV was obtained for strained BGaAsSb/GaAs QWs.

We have performed the first-principles density functional calculations of the electronic and optical properties of quaternary B x Ga 1− x As 1− y Sb y alloy lattice-matched to GaAs with boron concentration x = 3.125% and 6.25%. All the calculations have been performed after geometric optimization. The calculated results show that B x Ga 1− x As 1− y Sb y alloys have the direct band gap. The density of states of GaAs and BGaAsSb were analyzed. In addition, the optical properties have been studied with a scissors operator. The effects of B and Sb incorporation on the dielectric function, reflectivity, refractive index, absorption coefficient and energy loss function of lattice-matched B x Ga 1− x As 1− y Sb y alloys in the photon energy range of 0–20 eV are also discussed in detail. We find our calculated results can be in good agreement with the available experimental values.

The first-principle calculations based on density functional theory have been used to study the electronic and optical properties of zinc-blende BInGaAs quaternary alloy lattice-matched to GaAs. The calculated results show the band gap of BInGaAs alloy are direct and the band gap will reduce with the increment of boron and indium composition. The electronic structures of BInGaAs alloy are analyzed via the calculation of density of states. The variation of optical properties including dielectric function, absorption coefficient, reflectivity, refractive index and energy loss function of the alloy were also investigated in detail.

First-principle plane-wave pseudopotential calculations using the density-functional theory within the local density approximation (LDA) have been carried out to investigate the structural, electronic and thermodynamic properties of zinc-blende dilute nitride GaP1−xNx alloy. We have found that the unit cell volumes of GaP1−xNx alloys are smaller than the value calculated from the linear interpolation of GaN and GaP binary alloys and there exists a negative deviation from Vegard's law. The Ga–P and Ga–N bond lengths of GaP1−xNx alloys reveal a slight relaxation. The incorporation of nitrogen into GaP leads to the giant reduction of the bandgap energy. We have investigated the thermal stabilities and obtained the most stable configurations of the GaP1−xNx alloy. In addition, the formation enthalpies have also been calculated, which could explain the difficulty in nitrogen incorporation into GaP.

Through the adoption of critical point drying, doubly curved regions (DCR) observed on the III-V microtubes vanished. This process verified that the DCR does not result from the natural release of the residual strain energy.

The epitaxy of GaAs/Si(001) has been carried out via inserting different buffer layers and different SLSs by MOCVD. High quality epilayers were obtained by AlAs buffer layer and GaAs0.85P0.15/GaAs SLS.

InAs/GaAs quantum dots (QDs) were grown by Metal-Organic Chemical Vapour Deposition (MOCVD) in the Stranski-Krastanow growth mode. The influence of growth parameters such as V/III ratio, growth temperature, QDs deposit thickness and the deposition rate of the overgrowth layer have been investigated. Through the room temperature photoluminescence (PL) spectra, we have obtained the quantum dots’ characters. The growth of QDs is very sensitive to the parameters, and the parameters influence the QDs quality nonlinearly. After an extensive study of these growth parameters, we achieve a balance of all the growth parameters with which InAs/GaAs QDs with 80meV of full width at half maximum (FWHM) at 1.12μm have been achieved.

We present first-principles calculations of the band-gap properties of the zinc-blende BN, GaN and B x Ga 1-x N alloys. By 16-atom supercells to model a random alloy, the direct band-gap (Γ 15v -Γ 1c ) bowing of 5.0 eV is obtained for B x Ga 1-x N alloys in the range of 0~37.5%, and the bowing parameter increases by 0.043eV/%B with boron (B) composition increasing. In addition, our calculated results show that 0.8eV (1550nm) direct transition band-gap energy of B x Ga 1-x N y As 1-y lattice matches to Si can be theoretically obtained while boron (B) composition is 4% and nitrogen (N) composition is 16%.

Through improving fabrication process, short-side rolling phenomenon has been eliminated, and well-aligned long-side rolled-up III-V microtube arrays have been achieved. Finite element method (FEM) has been exploited to simulate the evolution of strain energy in the entire self-rolling process, showing that the difference of strain-released regions is the major factor that determines the rolling direction. Meanwhile, the doubly curved regions have been observed around the openings of air-dried microtubes but do not exist on the microtubes dried in critical point dryer, which demonstrates this structural deformation results not from the release of residual strain energy but from the surface tension.

In this research, 5-period highly-strained BInGaAs/GaAs multiple quantum wells (MQWs) have been successfully grown at 480-510ºC by LP-MOCVD. Room-temperature photoluminescence (RT-PL) measurements of BInGaAs/GaAs MQWs showed the peak wavelength as long as 1.17 μm with full-width at half maximum (FWHM) of only 29.5 meV. In addition, a slight blue-shift (∼18 meV) of PL peak energy of InxGa1-xAs/GaAs MQWs was observed after boron incorporation. It has been found boron incorporation ( 40%), the positive effect of boron incorporation prevailed, i.e., boron incorporation completely suppressed the thickness undulation and lead to the improvement of PL properties.

BGaAs alloys have been grown on GaAs substrate with different Ga precursor, TMGa and TEGa. With TEGa, it can grow at a lower temperature, and obtain a higher boron content than that grown with TMGa.

Highly-strained BInGaAs/GaAs quantum wells have been grown at low temperature by incorporating boron element into InGaAs/GaAs quantum wells. The effects of boron incorporation on the structural and optical properties of highly-strained InGaAs/GaAs QWs been investigated.