Band gap of Ge rich Si1−x−yGexCy alloys

Orner, B. A.; Olowolafe, J. O.; Roe, K.; Kolodzey, J.; Laursen, Thomas; Mayer, J. W.; Spear, J.

doi:10.1063/1.117738

Cited by 30 publications

(20 citation statements)

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“…These conditions place severe limits on the device structure. Nonetheless, considerable research has been undertaken on determining the optical properties of Si/ Si1−xGex heterostructures (Pearsall, 1994), which exhibit type I band alignment (People and Jackson, 1990;Houghton et al, 1995) (see Figure 1), and, to a lesser extent, on Si/Si1−xCx or even Si/Si1−x−yGex Cy (St Amour et al, 1995;Orner et al, 1996;Soref et al, 1996;Sturm, 1998).…”

Section: Band Structure Engineering Via Alloyingmentioning

confidence: 99%

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: Band Structure Engineering Via Alloyingmentioning

confidence: 99%

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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“…Here we consider deformation potential acoustic phonon scattering, intravalley scattering by optical phonons and intervalley scattering by acoustical phonons. The relaxation time for deformation potential acoustic phonon scattering is [12 -14] ( ) 3 …”

Section: Phonon Scatteringmentioning

confidence: 99%

“…Several authors noticed [2,3,11] that in Si 1-x Ge x structure, for x > 0.8, crossover of X and L valleys in the conduction band occurs and the band structure of the material resembles that of Ge. We have therefore assumed that the phonon scattering mechanisms in Ge-rich alloy is unaltered from that in Ge.…”

Section: Introductionmentioning

confidence: 99%

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Alloy and phonon scattering limited mobility in strain‐free ternary Si_1–x–yGe_xC_y

Mukhopadhyay

Basu

2004

Physica Status Solidi (b)

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Estimates are made of the mobility limited by alloy disorder and phonon scattering mechanisms in strain free Ge-rich ternary layer Si 1-x-y Ge x C y grown on Si substrate. The expression for alloy scattering potential in ternary was derived for the first time using virtual crystal approximation and it differs from the expressions for ternary and quaternary alloys of III -V compounds. The phonon scattering processes are taken to be identical with those in pure Ge. Conservative estimates of mobility made by using reasonable values of alloy scattering potential indicate that mobility is predominantly limited by alloy scattering for 0.85 < x < 1 and the effect of C mole fraction (y) is not much significant for y < 0.1.

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“…Alloying is typically done with germanium [7], although alloys of Si with C and Ge have also shown promise [8]. Silicon-germanium quantum wells superlattices have been successfully employed to achieve luminescence below the band-gap energy of silicon [9].…”

Section: Introductionmentioning

confidence: 99%

Monolithic Silicon Light Sources

Fauchet¹

2004

Topics in Applied Physics

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Abstract. Monolithic silicon light sources (LEDs and lasers) could have a significant impact when integrated on silicon chips. After a general introduction to light emission in silicon, this chapter discusses the mechanisms of light emission in bulk silicon, silicon quantum dots, silicon alloyed with germanium, and silicon doped with specific impurities such as erbium. Then, the fabrication and performance of LEDs using these materials are discussed. The chapter ends with a discussion of the prospects for a silicon laser.

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Band gap of Ge rich Si1−x−yGexCy alloys

Cited by 30 publications

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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

Alloy and phonon scattering limited mobility in strain‐free ternary Si_1–x–yGe_xC_y

Monolithic Silicon Light Sources

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Band gap of Ge rich Si1−x−yGexCy alloys

Cited by 30 publications

References 0 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

Alloy and phonon scattering limited mobility in strain‐free ternary Si1–x–yGexCy

Monolithic Silicon Light Sources

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Alloy and phonon scattering limited mobility in strain‐free ternary Si_1–x–yGe_xC_y