Investigation of the direct band gaps in Ge1−xSnx alloys with strain control by photoreflectance spectroscopy

Lin, Hai; Chen, Robert; Lü, Wei; Huo, Yijie; Kamins, Theodore I.; Harris, James S.

doi:10.1063/1.3692735

Cited by 113 publications

(83 citation statements)

References 13 publications

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“…The energy band structure is modified with tensile or compressive strain in Ge and Ge 1−x Sn x . There are many reports of the strain and Sn content dependence of the energy band gap and band structures estimated using optical transmittance spectroscopy [6], spectroscopic ellipsometry [7], Fourier transform infrared spectroscopy (FT-IR) [8], photoluminescence [9][10][11] and photoreflectance spectroscopy [12]. The Sn content of the direct-indirect crossover point increases (decreases) with the magnitude of the compressive (tensile) strain [13].…”

Section: Energy Band Structure Of Ge 1−x Sn X -Related Materialsmentioning

confidence: 99%

Growth and applications of GeSn-related group-IV semiconductor materials

Zaima

Nakatsuka

Asano

et al. 2016

2016 IEEE Photonics Society Summer Topical Meeting Series (SUM)

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We review the technology of Ge 1−x Sn x -related group-IV semiconductor materials for developing Si-based nanoelectronics. Ge 1−x Sn x -related materials provide novel engineering of the crystal growth, strain structure, and energy band alignment for realising various applications not only in electronics, but also in optoelectronics. We introduce our recent achievements in the crystal growth of Ge 1−x Sn x -related material thin films and the studies of the electronic properties of thin films, metals/Ge 1−x Sn x , and insulators/Ge 1−x Sn x interfaces. We also review recent studies related to the crystal growth, energy band engineering, and device applications of Ge 1−x Sn x -related materials, as well as the reported performances of electronic devices using Ge 1−x Sn x related materials.

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Section: Energy Band Structure Of Ge 1−x Sn X -Related Materialsmentioning

confidence: 99%

Growth and applications of GeSn-related group-IV semiconductor materials

Zaima

Nakatsuka

Asano

et al. 2016

2016 IEEE Photonics Society Summer Topical Meeting Series (SUM)

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“…However, the bandgap values can be measured to be at 0.63eV for Ge 0.95 Sn 0.05 and 0.57eV for Ge 0.91 Sn 0.09 . Due to the strain, these observed bandgaps are slightly higher compared to unstrained GeSn alloys [25][26][27][28]. In order to implement the photodetectors in a short-wave infrared system, measurements of the absolute responsivity in A/W at a fixed 5V bias were carried out using several calibrated fiber coupled sources.…”

Section: Photodetector Characterizationmentioning

confidence: 99%

GeSn/Ge heterostructure short-wave infrared photodetectors on silicon

Gassenq¹,

Gencarelli²,

Campenhout³

et al. 2012

Opt. Express

182

105

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A surface-illuminated photoconductive detector based on Ge 0.9 Sn 0.1 quantum wells with Ge barriers grown on a silicon substrate is demonstrated. Photodetection up to 2.2µm is achieved with a responsivity of 0.1 A/W for 5V bias. The spectral absorption characteristics are analyzed as a function of the GeSn/Ge heterostructure parameters. This work demonstrates that GeSn/Ge heterostructures can be used to developed SOI waveguide integrated photodetectors for short-wave infrared applications. 2012 Optical Society of America References and links1. J. Menendez and J. Kouvetakis "Type-I Ge/Ge1−x−ySixSny strained-layer hetero-structures with a direct Ge Bandgap", Applied Physics Letters, 85(7), 1175-1177 (2004). 2. G. Sun, R. A. Soref, H. H. Cheng, "Design of a Si-based lattice-matched room temperature GeSn/GeSiSn multiquantum-well mid-infrared laser diode", Optics Express 18(19), 19957-19965 (2010). 39(3), 1871-1883, (1989). 14. M. Krijn, "Heterojunction band offsets and effective masses in III-V quaternary alloys" Semiconductor Science and Technology, 6(1), 27-31 (1991

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“…Thanks to this tensile strain (+0.34% for 4.5% Sn) our layers show a direct transition for a Sn composition (4.5%) which is lower than for unstrained (6.4%) or compressively strained GeSn. 30 For the amorphous GeSn sample investigated in this work, we followed a similar approach: the absorption coefficient α was calculated from the extinction coefficient k and the incident wavelength λ 0 in free space as: α(λ 0 ) = 4πk/λ 0 . Subsequently we fitted the absorption coefficient α to the equation αhv = C A (hv − E g ) n with hv the photon energy, C A a constant that differs for different transitions, n is an index which depends on the transition, and E g the Tauc gap.…”

Section: Ecs Journal Of Solid State Science and Technology 3 (12) P4mentioning

confidence: 99%

Structural and Optical Properties of Amorphous and Crystalline GeSn Layers on Si

Lieten

Fleischmann

Peters

et al. 2014

ECS J. Solid State Sci. Technol.

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We have investigated the structural and optical properties of metastable amorphous and crystalline GeSn layers on Si substrates. The as-deposited amorphous layers crystallize during annealing at 500 • C. This transition leads to a significant change in the local environment of the Sn atoms and in the optical properties. The Ge-Sn bond length is decreased after crystallization. The as-deposited GeSn layers, with nominal 4.5% and 11.3% Sn content, do not show Sn segregation. For the crystallized GeSn with nominal 4.5%, the Sn appears to be substitutional, as no Sn clustering was observed. However, for the crystallized GeSn with nominal 11.3% Sn, Sn segration and the presence of β-Sn is observed by EXAFS. A method to suppress Sn segregation and increase the substitutional Sn concentration is discussed. Furthermore, we determined the optical properties of amorphous and crystalline GeSn with nominal 4.5% Sn. The bandgap energy decreases significantly from 0.89 eV (1392 nm) ± 0.05 eV for the amorphous layer to 0.52 eV (2383 nm) ± 0.05 eV for crystalline GeSn, leading to significant reduction in penetration depth.

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Investigation of the direct band gaps in Ge1−xSnx alloys with strain control by photoreflectance spectroscopy

Cited by 113 publications

References 13 publications

Growth and applications of GeSn-related group-IV semiconductor materials

Growth and applications of GeSn-related group-IV semiconductor materials

GeSn/Ge heterostructure short-wave infrared photodetectors on silicon

Structural and Optical Properties of Amorphous and Crystalline GeSn Layers on Si

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