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Choulis, Stelios A.; Hosea, T. J. C.; Tomić, Stanko; Kamal-Saadi, M.; Adams, A.R.; O’Reilly, Eoin P.; Weinstein, B. A.; Klar, Peter J.

doi:10.1103/physrevb.66.165321

Cited by 66 publications

(25 citation statements)

References 49 publications

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“…Our GaInNaAs/GaAs laser results are consistent with photo-modulated reflectance PR measurements of the QW transition energies performed on similar GaInNAs/GaAs QW wafer samples for which a strong sub-linear variation of band gap with pressure is observed over a wide pressure range [8]. Shan et al [9] report similar findings on GaInNAs/GaAs QWs for different nitrogen fractions using photomodulated transmission measurements under pressure.…”

Section: Pressure Effectssupporting

confidence: 87%

Hydrostatic pressure dependence of recombination mechanisms in GaInNAs, InGaAsP and AlGaInAs 1.3 μm quantum well lasers

Sweeney

Jin

Tomić

et al. 2003

Physica Status Solidi (b)

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From measurements of the threshold current and lasing energy as a function of pressure in InGaAsP/InP, AlGaInAs/InP and GaInNAs/GaAs based multiple quantum well lasers we determine the relative importance of the monomolecular, radiative and Auger recombination processes. For the InP based devices, we find that a simple combination of radiative and non-radiative Auger recombination can fully explain the pressure dependence of the threshold current where the threshold carrier density is approximately constant as a function of pressure. For the GaInNAs/GaAs devices we observe a large increase in threshold current with pressure. This we show is due to the interaction of the nitrogen level with the conduction band which gives rise to an increased conduction band effective mass resulting in an increase in threshold carrier density of ~12% over 10 kbar. This large increase in n th increases the monomolecular, radiative and unusually, the Auger recombination current with pressure explaining the large increase in threshold current with pressure.1 Introduction The development of cheap, temperature-insensitive lasers operating around 1.3 µm and 1.55 µm has for many years been the subject of great attention in the optoelectronics community. Due to the recent emergence and increased demand for metro and Cable Television (CATV) applications, research into efficient devices operating at these wavelengths has gained considerable momentum. The development of 1.3 µm lasers has grown relatively in importance as demand continues for short-haul communications links. In addition, semiconductor lasers operating over the range 1.4 µm to 1.5 µm are becoming of interest as laser pump sources for Raman amplifiers. The III-V materials system InGaAs(P)/InP has been successfully used to produce lasers at both 1.3 µm and 1.55 µm. In spite of the commercial success of these devices, they remain far from ideal due to material and structural dependent problems such as Auger recombination, optical losses and carrier leakage [1]. These give rise to both higher than optimum threshold current densities and high temperature sensitivity over the required temperature range of operation, (typically -4 0 °C to +80 °C), requiring complex and expensive temperature control circuitry. Alternative improved materials have been sought after to overcome these problems.

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Section: Pressure Effectssupporting

confidence: 87%

Hydrostatic pressure dependence of recombination mechanisms in GaInNAs, InGaAsP and AlGaInAs 1.3 μm quantum well lasers

Sweeney

Jin

Tomić

et al. 2003

Physica Status Solidi (b)

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“…where the subscripts N, CB, and VB stand for nitrogen-resonant, conduction band, valence bands, respectively; V Nc describes the interaction between the N state and the CB edge, and P 0 (k) the coupling between the CB and various VBs as a function of the in-plane wavevector k. The N-related band offset parameters γ and α describe the movement of nitrogen resonant level and CB edge with content of nitrogen (x), while a parameter κ takes account of the variation of the VB offset between strained InGaN x As 1-x and GaAs, as a function of x [10]. By matching to the measured PR QW transition energies of the dilute-N InGaNAs MQWs as a function of pressure, with the theoretical model, we found that α = 1.55 eV, γ = 3.5 eV and κ = 3.5 eV (These parameters were estimated from tight-binding calculations, however they minor varied in order to obtain the best match between experiment and theory).…”

Section: Matching Theory With Experimentsmentioning

confidence: 99%

“…To achieve the best match only the layer compositions and thicknesses were varied within the uncertainties set by growth conditions (see Table 1), with standard minor-scaling of the other k · p parameters, as appropriate (we discuss this point below). A detailed description of the 10-band Hamiltonian has been given elsewhere [10]. Here, we use the following schematic form:…”

Section: Figmentioning

confidence: 99%

Pressure and k · p studies of band parameters in dilute‐N GaInNAs/GaAs multiple quantum wells

Choulis

Hosea

Tomić

et al. 2003

Physica Status Solidi (b)

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We report pressure dependent photomodulated reflectance (PR) measurements on a series of dilute-N InGaNAs/GaAs multiple quantum wells (MQWs). Our experimental results indicate the presence of important N-related disorder effects due to different nearest-neighbour N-cation configurations The quantum well transition energies obtained from the PR spectra are modelled using a realistic 10-band k · p Hamiltonian that includes tight-binding-based energies and coupling parameters for the N-levels. By matching experiment with theory we are able to determine accurately the band structure and thus predict some important material parameters for dilute-N InGaAsN alloys.Introduction The ability to calculate effective masses and conduction band offsets is important for designing laser devices. Accurate knowledge of the band structure of the component materials is the first step to identifying these parameters. Although this can be a much easier procedure for well-known materials, it is much more difficult task for novel systems such as InGaNAs [1].InGaNAs differs considerably from the conventional III-V alloys and exhibits striking new properties [2], some of which are reviewed in this paper. In this new class of dilute-N III-N-V semiconductor alloys, modification in the band structure is achieved by N forming localised states which interact with the conduction band (CB) edge of the host semiconductor [3]. To investigate this complex band formation, modulation spectroscopy as a function of pressure, has proved to be a very useful tool [2][3][4]. Previously we reported the dramatic effects of increasing N-incorporation on the quantum well (QW) interband energies including negative bandgap-bowing, smaller total temperature variation, and strong decrease in the rate of pressure-shift (reduced linear shifts with larger sub-linear components) [4]. Here, we seek to gain a more comprehensive picture of the influence of nitrogen on the confined levels in In y Ga 1-y As 1-x N x /GaAs multiple quantum wells (QWs), including the effects of disorder due to different nearest-neighbour N-cation configurations [5]. We determine the band structure of dilute-N InGaNAs/GaAs (0 ≤ x ≤ 4.3%) MQWs, by combined pressure dependent photomodulated reflectance (PR) measurements and theoretical k · p studies. The accurate determination of the band-structure allows us to

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“…[58][59][60] The BAC model can be extended to treat ten bands (spindoubled conduction, valence, and nitrogen impurity bands) by modifying the 8-band k·p theory to include two extra spin-degenerate nitrogen states to describe the electronic band structure of GaNAs/GaAs and related heterostructures. [58][59][60][61][62] It was also argued that the electronic structure of GaNAs alloys is determined by interactions between nitrogen, X, L and Γ states 63,64 This provided more parameters to afford greater flexibility in fitting the experimental data. Although the BAC model does not consider anything more complicated than an interaction of randomly distributed localized nitrogen states with the extended states of the conduction band it properly describes all the main characteristics of the electronic structure of dilute nitrides.…”

Section: Band Anticrossingmentioning

confidence: 99%