Ge-on-Si approaches to the detection of near-infrared light

Colace, Lorenzo; Masini, G.; Assanto, Gaetano

doi:10.1109/3.806596

Cited by 123 publications

(48 citation statements)

References 31 publications

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“…The sleeves were used to extract photocurrent without substantially changing the antenna characteristics (from a bare dipole). Crystalline germanium was chosen to be the active material of our photodetector because of its high responsivity at near-infrared wavelengths and its compatibility with standard silicon technology 18 . Previous research has shown that use of a substrate with a high dielectric constant significantly weakens the antenna resonant strength 13 .…”

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confidence: 99%

Nanometre-scale germanium photodetector enhanced by a near-infrared dipole antenna

et al. 2008

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A critical challenge for the convergence of optics and electronics is that the micrometre scale of optics is significantly larger than the nanometre scale of modern electronic devices. In the conversion from photons to electrons by photodetectors, this size incompatibility often leads to substantial penalties in power dissipation, area, latency and noise [1][2][3][4] . A photodetector can be made smaller by using a subwavelength active region; however, this can result in very low responsivity because of the diffraction limit of the light. Here we exploit the idea of a half-wave Hertz dipole antenna (length 380 nm) from radio waves, but at near-infrared wavelengths (length 1.3 mm), to concentrate radiation into a nanometre-scale germanium photodetector. This gives a polarization contrast of a factor of 20 in the resulting photocurrent in the subwavelength germanium element, which has an active volume of 0.00072 mm 3 , a size that is two orders of magnitude smaller than previously demonstrated detectors at such wavelengths.The interaction of light with nanostructured metals has been studied extensively in recent years [5][6][7][8][9][10] . The resulting near-field optical intensity can be two to three orders of magnitude higher than the incident intensity. However, very little research has been carried out into the interaction of these strong near fields with semiconductors and the further transformation of the optical energy into electricity [11][12][13] . It has recently been demonstrated that the photogeneration of carriers in silicon can be enhanced by a surface-plasmon antenna at a wavelength of 840 nm (ref. 12). This method has the practical limitation that the entire grating structure necessary for exciting a surface-plasmon resonance occupies a large area in terms of wavelengths. Alternatively, a C-shaped aperture has been used to enhance photodetection locally without exciting long-range surface-plasmon resonances 13 . However, for easy integration and high-speed, low-capacitance operation, it is generally advantageous to design planar devices such as the metal -semiconductor-metal (MSM) detectors that are widely used in high-speed optical receivers 14 .Resonant antennas can confine strong optical near fields in a subwavelength volume, as demonstrated recently for bow-tie antennas and dipole antennas at visible wavelengths using the resulting scattered light 15,16 . The optical properties of the structures largely depend on the size and shape of the antennas.

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Nanometre-scale germanium photodetector enhanced by a near-infrared dipole antenna

et al. 2008

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“…This enables a significant reduction in the dislocation density of the as-grown Ge epilayer, thereby improving the detector's dark current performance. In yet another approach, Colace et al (1999) proposed a direct hetero-epitaxy growth of Ge on Si through the use of a low temperature thin SiGe buffer layer (a few 10nm). The insertion of such thin buffer avoids the occurrence of 3D SK growth, and allows the misfit dislocations to be concentrated at the hetero-interfaces.…”

Section: Hetero-epitaxy Of Germanium On Siliconmentioning

confidence: 99%

Germanium Photodetector Technologies for Optical Communication Applications

Ang¹,

Lo²,

Kwong³

2010

Semiconductor Technologies

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“…For particular photonic functions like light amplification and electrically pumped lasers at telecom wavelengths, the InP/InGaAsP material system remains the material of choice, despite significant research in Silicon based active opto-electronic devices [2] [3]. For detection of light at telecom wavelengths, both InP/InGaAsP and Germanium are being envisaged for integration on a Silicon platform [4] [5]. Therefore, in this paper we will focus on the integration of InP/InGaAsP laser diodes and photodetectors on top of an SOI waveguide circuit.…”

Section: Introductionmentioning

confidence: 99%