GeSn <i>p-i-n</i> waveguide photodetectors on silicon substrates

Peng, Yu-Hsiang; Cheng, Huang; Mashanov, V. I.; Chang, Guo‐En

doi:10.1063/1.4903881

Cited by 97 publications

(50 citation statements)

References 31 publications

(36 reference statements)

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“…With a Sn content of x > 2%, the cutoff wavelength of the photodetection range can be extended beyond 1675 nm to fully cover the entirety of the fiberoptic telecommunication bands. Furthermore, compared to the typical responsivity of about 0.15 A/W for the GeSn p-i-n PDs [13], the Ge 1−x Sn x HPTs exhibit a much higher responsivity in the spectral range, owing to the current gain provided by the HPT structure. This indicates that the use of Ge 1−x Sn x HPTs not only achieves the extended photodetection range, but can also considerably enhanced responsivity.…”

Section: Theoretical Results and Discussionmentioning

confidence: 98%

“…With a smaller bandgap, the absorption edge of GeSn alloys can be considerably extended from 1.55 µm to the mid-infrared region, and the absorption coefficients can be significantly enhanced. Based on this development, different groups have demonstrated GeSn-based PDs with enhanced optical responsivity and an extended long-wavelength spectral response that reaches beyond 2.4 µm [6]- [13], thus covering the entirety of the fiber-optic telecommunication windows. However, the responsivities of the GeSn PDs are still limited, which prevents them from achieving the efficient photodetection required for EPIC applications.…”

Section: Introductionmentioning

confidence: 96%

“…The structure consists of a fully strain-relaxed Ge buffer layer with a thickness of 200 nm grown on a Si(001) substrate; this buffer layer severs as the virtual substrate (VS). The Ge VS can be realized using two-step growth techniques [10], [13], [26], [27], and it can confine threading dislocations caused by lattice mismatch at the Ge/Si interface to improve the material quality for the GeSn active region. Next, a 200 nm thick ntype Ge sub-collector layer is grown, followed by a 100 nm thick n-type Ge 1−x Sn x collector layer.…”

Section: Introductionmentioning

confidence: 99%

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Design and Modeling of GeSn-Based Heterojunction Phototransistors for Communication Applications

Chang

Basu

Mukhopadhyay

et al. 2016

IEEE J. Select. Topics Quantum Electron.

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We propose the use of Ge1−xSnx heterojunction phototransistors (HPTs) as efficient optical receivers on Si substrates and analyze their performance. Our designs use n-Ge/pGe1−xSnx/n-Ge1−xSnx layers pseudomorphically grown on Si wafers via a Ge virtual substrate, which offers compatibility with complementary metal-oxide-semiconductor (CMOS) technology. By incorporating Sn into the Ge photon-absorbing layer to shrink the bandgap, the photodetection range can be significantly extended to the mid-infrared (MIR) region with a considerably enhanced optical response. The use of HPT structures provides optical conversion gain to further enhance the optical responsivity, thereby enabling efficient photodetection in the shortwave infrared region. We develop theoretical models to calculate the composition-dependent band alignments, the band structures (by taking into account the nonparabolic effect), the absorption coefficient, and the optical responsivity for the proposed GeSn HPTs. As the Sn content increases, the conduction band nonparabolicity becomes increasingly significant and considerably impacts the optical absorption coefficient. Moreover, analysis of the spectral response for the Ge1−xSnx HPTs shows that efficient photodetection covering the entirety of the fiber-optic telecommunication bands, as well as the emerging 2 µm MIR communication band, can be achieved. These results indicate that the proposed Ge1−xSnx HPTs are attractive for use as highresponsivity CMOS-compatible photodetectors in communication applications.

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Section: Theoretical Results and Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Design and Modeling of GeSn-Based Heterojunction Phototransistors for Communication Applications

Chang

Basu

Mukhopadhyay

et al. 2016

IEEE J. Select. Topics Quantum Electron.

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“…GeSn has also been widely reported for photodetection, and a relatively higher concentration of 9%-10% Sn has been used to demonstrate photodetector and photoconductor for 2.2-2.4 μm wavelengths in [19] and [20], respectively. A waveguide GeSn photodetector has been reported in [21]. Therefore it is feasible to realize a monolithically integrated GeSn sensor for wavelengths near 2.2 μm in order to detect greenhouse gases such a CO 2 .…”

Section: Introductionmentioning

confidence: 99%

Towards low-loss waveguides in SOI and Ge-on-SOI for mid-IR sensing

et al. 2018

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Silicon-on-insulator is an attractive choice for developing mid-infrared photonic integrated circuits. It benefits from mature fabrication technologies and integration with on-chip electronics. We report the development of SOI channel and rib waveguides for mid-infrared wavelengths centered at 3.7 μm. Propagation loss of ∼1.44 dB/cm and ∼1.2 dB/cm has been measured for TE and TM polarizations in channel waveguides, respectively. Similarly, propagation loss of ∼1.39 dB/cm and ∼2.82 dB/cm has been measured for TE and TM polarized light in rib waveguides. The propagation loss is consistent with the measurements obtained using a different characterization setup and for the same waveguide structures on a different chip. Given the tightly confined single-mode in our 400 nm thick Si core, this propagation loss is among the lowest losses reported in literature. We also report the development of Ge-on-SOI strip waveguides for mid-infrared wavelengths centered at 3.7 μm. Minimum propagation loss of ∼8 dB/cm has been measured which commensurate with that required for high power midinfrared sensing. Ge-on-SOI waveguides provide an opportunity to realize monolithically integrated circuit with on-chip light source and photodetector.

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“…The alloy may show direct gap for Sn concentration exceeding 8% or by applying tensile strain [2]. Many workers in recent years are trying to exploit the direct gap of the alloy to develop lasers [4] or photodetectors [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Signal-to-noise ratio for a Ge-GeSn-GeSn Hetero PhotoTransistors at 1.55 µm

Basu

Chakraborty

Mukhopadhyay

et al. 2015

2015 6th International Conference on Computers and Devices for Communication (CODEC)

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Heterojunction Photo Transistors (HPTs) provide optical gain but no excess noise. Recently good quality alloys of GeSn are regularly grown on Si substrate, opening up the possibility of having lasers, photodetectors etc. using standard VLSI technology. In this paper signal-to-noise ratio (SNR) for an HPT having GeSn as base has been estimated at telecommunication wavelength of 1.55 µm.The calculated gain-bandwidth product indicates high values and satisfactory SNR.

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GeSn p-i-n waveguide photodetectors on silicon substrates

Cited by 97 publications

References 31 publications

Design and Modeling of GeSn-Based Heterojunction Phototransistors for Communication Applications

Design and Modeling of GeSn-Based Heterojunction Phototransistors for Communication Applications

Towards low-loss waveguides in SOI and Ge-on-SOI for mid-IR sensing

Signal-to-noise ratio for a Ge-GeSn-GeSn Hetero PhotoTransistors at 1.55 µm

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