GeSi infrared detectors

Strong, R.; Greve, D. W.; Misra, R.; Weeks, Melanie M.; Pellegrini, P.W.

doi:10.1016/s0040-6090(96)09231-0

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…This feature also indicates that the Ge/Si self-assembled clusters are not equivalent to heterojunctions like those used for internal photoemission sensors. 15 In conclusion, we have shown that Ge/Si self-assembled quantum dots exhibit intraband absorption in the midinfrared spectral range ͑4 m wavelength͒. The intraband absorption is in-plane polarized with a very large absorption cross section.…”

confidence: 74%

Intraband absorption in Ge/Si self-assembled quantum dots

Boucaud

Thanh

Sauvage

et al. 1999

Applied Physics Letters

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We have observed intraband absorption in Ge/Si self-assembled quantum dots. The self-assembled quantum dots are grown at 550 °C by chemical vapor deposition. Atomic force microscopy shows that the quantum dots have a square-based pyramidal shape (≈100 nm base length) and a density ≈2×109 cm−2. Intraband absorption in the valence band is observed around 300 meV (4.2 μm wavelength) using a photoinduced spectroscopy technique. The intraband absorption is in-plane polarized. It is attributed to bound-to-continuum transitions since the intraband energy corresponds to the energy difference between the Si band gap and the photoluminescence energy of the quantum dots. The magnitude of the intraband absorption saturates when the ground level of the quantum dots is filled. This feature allows the measurement of the in-plane absorption cross section of the intraband transition which is found as large as 2×10−13 cm2.

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confidence: 74%

Intraband absorption in Ge/Si self-assembled quantum dots

Boucaud

Thanh

Sauvage

et al. 1999

Applied Physics Letters

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“…3,4,8,15,16,18 A simple sketch of the band diagram showing the valence band profile of a heavily p-doped (2ϫ10 20 cm Ϫ3 ͒ SiGe 0.35 well surrounded by two undoped Si spacer layers can be seen in Fig. 3,4,8,15,16,18 A simple sketch of the band diagram showing the valence band profile of a heavily p-doped (2ϫ10 20 cm Ϫ3 ͒ SiGe 0.35 well surrounded by two undoped Si spacer layers can be seen in Fig.…”

Section: Theorymentioning

confidence: 99%

Novel mid-infrared silicon/germanium detector concepts

et al. 2000

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Highly p-doped silicon/silicon-germanium (Si/SiGe) quantum well (QW) structures are grown by molecular beam epitaxy (MBE) on double-sided polished ͗100͘Si substrates for mid-IR (3 to 5 m and 8 to 12 m) detection. The samples are characterized by secondary ion mass spectroscopy (SIMS), x-ray diffraction, and absorption measurements. Single mesa detectors are fabricated as well as large-area focal plane arrays (FPAs) with 256ϫ256 pixels using standard Si integrated processing techniques. The detectors, based on heterointernal photoemission (HIP) of photogenerated holes from a heavily p-doped (p ϩϩ ϳ5ϫ10 20 cm Ϫ3 ) SiGe QW into an undoped silicon layer, operate at 77 K. Various novel designs of the SiGe HIP's such as Ge-and B-grading, double-and multi-wells, are realized; in addition, thin doping setback layers between the highly doped well and the undoped Si layer are introduced. The temperature dependence of dark currents and photocurrents are measured up to 225 K. In general, we observe broad photoresponse curves with peak external quantum efficiencies up to ext ϳ0.5% at 77 K and 4, detectivities up to 8ϫ10 11 cmͱHz/W are obtained. We demonstrate that by varying the thickness, Ge content, and doping level of the single-and the multi-QWs of SiGe HIP detectors, the photoresponse peak and the cutoff of the spectrum can be tuned over a wide wavelength range. The epitaxial versatility of the Si/SiGe system enables a tailoring of the photoresponse spectrum which demonstrates the advantages of the SiGe system in comparison over commercially used silicide detectors.

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“…There have been numerous attempts to design heterostructures of Si and Ge with the intention to make, for example, infrared detectors [1][2][3]. The task is then to optimize the key figures of merit (quantum efficiency, dark current, bandwidth) at the favoured operational wavelengths, i.e.…”

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confidence: 99%

Si/Ge self-assembled quantum dots for infrared applications

Cusack

Briddon

North

et al. 2001

Semicond. Sci. Technol.

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We introduce Si/Ge self-assembled quantum dots for infrared applications operating in the 3-5 µm range. Conventional Si/Ge quantum well structures are transparent to such wavelengths in the absence of heavy doping. We show that the high degree of strain lowers the bandgap and also that the electrons and holes are both localized in the interfacial region. This will consequently enhance the optical transition probabilities.

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GeSi infrared detectors

Cited by 5 publications

References 13 publications

Intraband absorption in Ge/Si self-assembled quantum dots

Intraband absorption in Ge/Si self-assembled quantum dots

Novel mid-infrared silicon/germanium detector concepts

Si/Ge self-assembled quantum dots for infrared applications

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