Silicon photonics: a bright future?

Paul, Douglas J.

doi:10.1049/el.2009.1271

Cited by 40 publications

(30 citation statements)

References 13 publications

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“…With a direct bandgap only ∼ 140 meV above the indirect valley [1], Ge has the potential to be an active CMOS compatible optical material [5]. Tensile strain has been demonstrated to decrease the difference between the direct and indirect bandgaps, enhancing the poor radiative recombination efficiency of the material by increasing the direct bandgap contribution.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Ge micro-cavities with in-plane tensile strains above 2 %

Millar¹,

Gallacher²,

Frigerio³

et al. 2016

Opt. Express

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Ge on Si micro-disk, ring and racetrack cavities are fabricated and strained using silicon nitride stressor layers. Photoluminescence measurements demonstrate emission at wavelengths ≥ 2.3 μm, and the highest strained samples demonstrate in-plane, tensile strains of > 2 %, as measured by Raman spectroscopy. Strain analysis of the micro-disk structures demonstrate that shear strains are present in circular cavities, which can detrimentally effect the carrier concentration for direct band transitions. The advantages and disadvantages of each type of proposed cavity structure are discussed.

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Section: Introductionmentioning

confidence: 99%

Analysis of Ge micro-cavities with in-plane tensile strains above 2 %

Millar¹,

Gallacher²,

Frigerio³

et al. 2016

Opt. Express

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“…2 For all these applications, sources of mid-infrared light and photodetectors 1,3 are key to enable any application. III-V and II-VI semiconductor materials have dominated over the last decades with both interband and intersubband emission and/or absorption devices, 1,3,4 but there is now significant interest in developing technology on silicon substrates [5][6][7] to enable far cheaper systems for mass market applications in environmental sensing, personalised healthcare, and security. 2,8 SiGe quantum well (QW) intersubband photodetectors (QWIPs) have previously been demonstrated, [9][10][11] but the number of QWs was limited by the SiGe critical thickness, thereby limiting performance.…”

Section: Introductionmentioning

confidence: 99%

8-band k·p modelling of mid-infrared intersubband absorption in Ge quantum wells

Paul

2016

Journal of Applied Physics

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The 8-band k·p parameters which include the direct band coupling between the conduction and the valence bands are derived and used to model optical intersubband transitions in Ge quantum well heterostructure material grown on Si substrates. Whilst for Si rich quantum wells the coupling between the conduction bands and valence bands is not important for accurate modelling, the present work demonstrates that the inclusion of such coupling is essential to accurately determine intersubband transitions between hole states in Ge and Ge-rich Si1−xGex quantum wells. This is due to the direct bandgap being far smaller in energy in Ge compared to Si. Compositional bowing parameters for a range of the key modelling input parameters required for Ge/SiGe heterostructures, including the Kane matrix elements, the effective mass of the Γ2′ conduction band, and the Dresselhaus parameters for both 6- and 8-band k·p modelling, have been determined. These have been used to understand valence band intersubband transitions in a range of Ge quantum well intersubband photodetector devices in the mid-infrared wavelength range.

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“…Germanium has received significant attention as an optical material in recent years, as it has the potential to enable active, CMOS compatible, photonics components [1,2]. It has a direct bandgap (Γ-valley) which is only 140 meV larger than the indirect bandgap, allowing for the potential of emitters such as lasers [3,4] and LEDs [5], as well as waveguides [6], photodetec-tors [7,8], and modulators [9,10], all on a Si platform.…”

Section: Introductionmentioning

confidence: 99%

Extending the emission wavelength of Ge nanopillars to 225 μm using silicon nitride stressors

Millar¹,

Gallacher²,

Samarelli³

et al. 2015

Opt. Express

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Abstract:The room temperature photoluminescence from Ge nanopillars has been extended from 1.6 μm to above 2.25 μm wavelength through the application of tensile stress from silicon nitride stressors deposited by inductively-coupled-plasma plasma-enhanced chemical-vapour-deposition. Photoluminescence measurements demonstrate biaxial equivalent tensile strains of up to ∼ 1.35% in square topped nanopillars with side lengths of 200 nm. Biaxial equivalent strains of 0.9% are observed in 300 nm square top pillars, confirmed by confocal Raman spectroscopy. Finite element modelling demonstrates that an all-around stressor layer is preferable to a top only stressor, as it increases the hydrostatic component of the strain, leading to an increased shift in the band-edge and improved uniformity over top-surface only stressors layers. Bridging the gap between theory and experiment," J. Appl. Phys. 79, 7148-7156 (1996).

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Silicon photonics: a bright future?

Cited by 40 publications

References 13 publications

Analysis of Ge micro-cavities with in-plane tensile strains above 2 %

Analysis of Ge micro-cavities with in-plane tensile strains above 2 %

8-band k·p modelling of mid-infrared intersubband absorption in Ge quantum wells

Extending the emission wavelength of Ge nanopillars to 225 μm using silicon nitride stressors

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