The Ge−Sn (Germanium−Tin) system

Olesinski, R. W.; Abbaschian, G. J.

doi:10.1007/bf02868550

Cited by 138 publications

(91 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…High-resolution TEM images reveal (Figure 2e-f) predominantly singe-crystalline particles, which is consistent with the size obtained from Scherer line-broadening analysis in XRD and SAXS. Lattice spacing in the (111) direction determined using intensity line scans across the inverse FFT of high-resolution images (Figures 2b) were in good agreement with those observed in XRD measurements.Although the solubility of Sn in bulk cubic Ge is quite low (~1%),33 our observations are consistent with the persistence of a highly crystalline, homogenous Sn x Ge 1-x alloy even at Sn…”

supporting

confidence: 88%

Sn_xGe_1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

Ramasamy¹,

Kotula²,

Fidler³

et al. 2015

Chem. Mater.

104

View full text Add to dashboard Cite

Non-toxic, sustainable and cost-effective, Group IV materials are attractive for a broad range of electronic and opto-electronic applications, although the indirect principal band gaps of silicon and germanium (Ge) present complications that impact device design and cost. Previous studies have shown that the band structures of these materials can be modified by the influence of quantum confinement in nanostructures, or by alloying with tin (Sn) in metastable thin films;to date, neither method has produced a material with a direct band gap of appropriate energy for application in, e.g., efficient solar photovoltaics. We have developed a facile colloidal method for the synthesis of size-controlled, homogeneous Sn x Ge 1-x alloy nanocrystals (NCs) with remarkably high tin concentration (x up to 0.42). We demonstrate that NCs of the same size exhibit a pronounced, systematic red-shift in the optical band gap, and a significant increase in molar absorptivity, with increasing Sn-content, and a measurable photoluminescence was observed from NCs with high contents. The indications of at least partial direct-gap character in these NCs, combined with their broad tunability throughout the infrared, suggest their promise for use in solution-processed solar cells.

show abstract

supporting

confidence: 88%

Sn_xGe_1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

Ramasamy¹,

Kotula²,

Fidler³

et al. 2015

Chem. Mater.

104

View full text Add to dashboard Cite

show abstract

“…In terms of possible disorder introduced by ion implantation, the TEM image in Fig. 4(c) of the as-implanted 2:1 Â 10 16 ion cm À2 sample clearly shows a surface pit within the amorphous layer having dimensions of about 400 nm in width and 50 nm in depth. These dimensions are close to that of the defects in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…However, achieving high quality crystalline Ge 1Àx Sn x with above 6:5 at: %Sn is challenging as the material is unstable at high Sn concentration because the solid solubility of Sn in Ge at ambient temperature is about 0:5 at: % . 16 For this reason, a non-equilibrium technique is essential for growing the alloy, such as molecular beam epitaxy (MBE), 10,11,17 sputter deposition, 18 or chemical vapour deposition (CVD). 15,19,20 Alternatively, ion-beam synthesis combined with nanosecond pulsed laser melting (PLM) can also provide a condition far from equilibrium 21 for achieving supersaturated Sn concentrations in Ge.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Ge1−xSnx alloys by ion implantation and pulsed laser melting: Towards a group IV direct bandgap material

Tran

Pastor

Gandhi

et al. 2016

Journal of Applied Physics

View full text Add to dashboard Cite

The germanium-tin (Ge1−xSnx) material system is expected to be a direct bandgap group IV semiconductor at a Sn content of 6.5−11 at. %. Such Sn concentrations can be realized by non-equilibrium deposition techniques such as molecular beam epitaxy or chemical vapour deposition. In this report, the combination of ion implantation and pulsed laser melting is demonstrated to be an alternative promising method to produce a highly Sn concentrated alloy with a good crystal quality. The structural properties of the alloys such as soluble Sn concentration, strain distribution, and crystal quality have been characterized by Rutherford backscattering spectrometry, Raman spectroscopy, x ray diffraction, and transmission electron microscopy. It is shown that it is possible to produce a high quality alloy with up to 6.2 at. %Sn. The optical properties and electronic band structure have been studied by spectroscopic ellipsometry. The introduction of substitutional Sn into Ge is shown to either induce a splitting between light and heavy hole subbands or lower the conduction band at the Γ valley. Limitations and possible solutions to introducing higher Sn content into Ge that is sufficient for a direct bandgap transition are also discussed.

show abstract

“…In principle, the growth of Sn-rich bulk GeSn alloys is limited by the maximum solubility of 1.1% at 400°C [28] or the poor thermal stability of richer alloys [29][30]. But it has been proved that the metastable miscibility gap could be largely reduced (~ 20% in composition) for Ga 1-x In x As y Sb 1-y /GaSb by taking into account the 2 .  strain energy [31].…”

Section: Experimental Challenge Of the Proposed Structurementioning

confidence: 99%

Stark shift of the absorption spectra in Ge/Ge1−Sn /Ge type-I single QW cell for mid-wavelength infra-red modulators

Yahyaoui

Sfina

Lazzari

et al. 2015

Superlattices and Microstructures

View full text Add to dashboard Cite

For mid-wavelength infra-red (MWIR) modulation or detection applications, we propose α-Sn rich Ge/Ge 1-x Sn x /Ge a type-I single quantum wells (SQW) partially strain compensated on Ge 1-y Sn y relaxed layers grown onto (001)-oriented Ge substrate. Such elementary cells with W-like potential profiles of conduction and valence bands have been modeled by solving the one-dimensional Schrödinger equation under an applied external electrical field. First, strain effects on electrons, heavy holes (hh) and light holes (lh) energy bands for strained/relaxed Ge 1-x Sn x /Ge 1-y Sn y heterointerfaces are investigated using the modelsolid theory in the whole ranges (0  x, y  1) of Sn compositions. From the obtained band-discontinuities, band gaps and effective masses, Ge 1-y Sn y /Ge/Ge 0.80 Sn 0.20 /Ge/Ge 1-y Sn y cells are computed as a function of the Ge 0.80 Sn 0.20 well width for three compositions of the Ge 1-y Sn y buffer layer (y=0.05, 0.07 and 0.09) in order to get the optimum quantum confinement of electrons and holes levels while keeping a reasonable amount of averaged strain in the cell. The electric field effect on the absorption spectra is given. An absorption coefficient in the 6  to 3  10 3 cm −1 range is reasonably obtained for a SQW at room temperature with a rather large Stark shift of the direct transition between 0.46 and 0.38 eV (i.e., λ=3.26-2.70 μm) at large external fields (50 kV/cm). These characteristics are attractive for the design of MWIR optical modulators.

show abstract

The Ge−Sn (Germanium−Tin) system

Cited by 138 publications

References 19 publications

Sn_xGe_1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

Sn_xGe_1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

Synthesis of Ge1−xSnx alloys by ion implantation and pulsed laser melting: Towards a group IV direct bandgap material

Stark shift of the absorption spectra in Ge/Ge1−Sn /Ge type-I single QW cell for mid-wavelength infra-red modulators

Contact Info

Product

Resources

About

The Ge−Sn (Germanium−Tin) system

Cited by 138 publications

References 19 publications

SnxGe1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

SnxGe1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

Synthesis of Ge1−xSnx alloys by ion implantation and pulsed laser melting: Towards a group IV direct bandgap material

Stark shift of the absorption spectra in Ge/Ge1−Sn /Ge type-I single QW cell for mid-wavelength infra-red modulators

Contact Info

Product

Resources

About

Sn_xGe_1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics

Sn_xGe_1–x Alloy Nanocrystals: A First Step toward Solution-Processed Group IV Photovoltaics