Three-Dimensional Silicon–Germanium Nanostructures for CMOS-Compatible Light Emitters

Lockwood, D. J.; Tsybeskov, L.

doi:10.1007/978-1-4419-7454-9_2

Cited by 10 publications

(18 citation statements)

References 101 publications

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“…The PL spectra typically observed in 3D Si/SiGe NSs is similar to that found for III-V QWs with type II energy band alignment, as the PL exhibits a blue shift on increasing the excitation intensity (Lockwood and Tsybeskov, 2010). This effect is found in samples grown by both MBE and CVD.…”

Section: Photoluminescence From Sige Nanostructuressupporting

confidence: 71%

“…Under much higher photoexcitation intensity (1-10 kW/cm 2 ), the low energy part of the PL spectrum does not shift any further, while the high energy part continues shifting toward higher energy. A modified Arrhenius plot of the normalized integrated PL intensity as a function of temperature for the different excitation intensities can be fitted with two thermal quenching activation energies, E1 and E2 (Lockwood and Tsybeskov, 2010). Activation energy E1 is found to be ~15 meV and is independent of the excitation intensity for all samples.…”

Section: Photoluminescence From Sige Nanostructuresmentioning

confidence: 95%

“…Low-temperature PL dynamics have been measured for a CVD grown sample using a ~6-ns excitation pulse at 2.33 eV (532 nm) (Lockwood and Tsybeskov, 2010). The initial PL decay is fast (< 20 ns), close to the resolution of the detection system.…”

Section: Photoluminescence From Sige Nanostructuresmentioning

confidence: 98%

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Si/SiGe Heterointerfaces in One-, Two-, and Three-Dimensional Nanostructures: Their Impact on SiGe Light Emission

Lockwood

Baribeau

et al. 2016

Front. Mater.

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Fast optical interconnects together with an associated light emitter that are both compatible with conventional Si-based complementary metal-oxide-semiconductor (CMOS) integrated circuit technology is an unavoidable requirement for the next-generation microprocessors and computers. Self-assembled Si/Si1−xGex nanostructures (NSs), which can emit light at wavelengths within the important optical communication wavelength range of 1.3-1.55 μm, are already compatible with standard CMOS practices. However, the expected long carrier radiative lifetimes observed to date in Si and Si/Si1−xGex NSs have prevented the attainment of efficient light-emitting devices, including the desired lasers. Thus, the engineering of Si/ Si1−xGex heterostructures having a controlled composition and sharp interfaces is crucial for producing the requisite fast and efficient photoluminescence (PL) at energies in the range of 0.8-0.9 eV. In this paper, we assess how the nature of the interfaces between SiGe NSs and Si in heterostructures strongly affects carrier mobility and recombination for physical confinement in three dimensions (corresponding to the case of quantum dots), two dimensions (corresponding to quantum wires), and one dimension (corresponding to quantum wells). The interface sharpness is influenced by many factors, such as growth conditions, strain, and thermal processing, which in practice can make it difficult to attain the ideal structures required. This is certainly the case for NS confinement in one dimension. However, we demonstrate that axial Si/Ge nanowire (NW) heterojunctions (HJs) with a Si/ Ge NW diameter in the range 50-120 nm produce a clear PL signal associated with bandto-band electron-hole recombination at the NW HJ that is attributed to a specific interfacial SiGe alloy composition. For three-dimensional confinement, the experiments outlined here show that two quite different Si1−xGex NSs incorporated into a Si0.6Ge0.4 wavy superlattice structure display PL of high intensity while exhibiting a characteristic decay time that is up to 1000 times shorter than that found in conventional Si/SiGe NSs. The non-exponential PL decay found experimentally in Si/SiGe NSs can be interpreted as resulting from variations in the separation distance between electrons and holes at the Si/SiGe heterointerface. The results demonstrate that a sharp Si/SiGe heterointerface acts to reduce the carrier radiative recombination lifetime and increase the PL quantum efficiency, which makes these SiGe NSs favorable candidates for future light-emitting device applications in CMOS technology.

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Section: Photoluminescence From Sige Nanostructuressupporting

confidence: 71%

Section: Photoluminescence From Sige Nanostructuresmentioning

confidence: 95%

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Si/SiGe Heterointerfaces in One-, Two-, and Three-Dimensional Nanostructures: Their Impact on SiGe Light Emission

Lockwood

Baribeau

et al. 2016

Front. Mater.

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“…Later, it was also shown that 3D Si/SiGe NSs exhibit an extremely long (~10 -2 s) luminescence lifetime [6], which is ~10 6 times longer than in III-V semiconductors and their NSs. Thus, according to that analysis, 3D Si/SiGe NSs cannot be used to achieve efficient and commercially valuable light emitting devices.…”

mentioning

confidence: 98%

Fast light-emitting silicon-germanium nanostructures for optical interconnects

Lockwood

2011

2011 ICO International Conference on Information Photonics

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“…Furthermore, there is an increased dispersion in the experimental data at small QW dimensions, which is missed in our model. This feature could be a result of an increased concentration of oxygen vacancy defect states at the interface [26,43], due to an error in the measurement of the QW dimension [21,40,44], or possibly because the carriers experience a stronger confinement energy from an additional mechanism not considered here. Nonetheless, our model is in good agreement with the experimental data.…”

Section: Gap Energy In γ-Spacementioning

confidence: 99%

Quantum confinement in nonadditive space with a spatially dependent effective mass for Si and Ge quantum wells

Barbagiovanni¹,

Filho²

2014

Physica E: Low-dimensional Systems and Nanostructures

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We calculate the effect of a spatially dependent effective mass (SPDEM) [adapted from R. N. Costa Filho et al.Phys. Rev. A., 84 050102 (2011)] on an electron and hole confined in a quantum well (QW). In the work of Costa Filho et al., the translation operator is modified to include an inverse character length scale, γ, which defines the SPDEM.The introduction of γ means translations are no longer additive. In nonadditive space, we choose a 'skewed' Gaussian confinement potential defined by the replacement x → γ −1 ln(1 + γx) in the usual Gaussian potential. Within the parabolic approximation γ is inversely related to the QW thickness and we obtain analytic solutions to our confinement Hamiltonian. Our calculation yields a reduced dispersion relation for the gap energy (E G ) as a function of QW thickness,Additionally, nonadditive space contracts the position space metric thus increasing the occupied momentum space and reducing the effective mass, in agreement the relation:The change in the effective mass is shown to be a function of the confinement potential via a point canonical transformation. Our calculation agrees with experimental measurements of E G for Si and Ge QWs.

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Three-Dimensional Silicon–Germanium Nanostructures for CMOS-Compatible Light Emitters

Cited by 10 publications

References 101 publications

Si/SiGe Heterointerfaces in One-, Two-, and Three-Dimensional Nanostructures: Their Impact on SiGe Light Emission

Si/SiGe Heterointerfaces in One-, Two-, and Three-Dimensional Nanostructures: Their Impact on SiGe Light Emission

Fast light-emitting silicon-germanium nanostructures for optical interconnects

Quantum confinement in nonadditive space with a spatially dependent effective mass for Si and Ge quantum wells

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