A new route toward light emission from Ge: tensile-strained quantum dots

Chen, Qimiao; Song, Yuxin; Wang, Kai; Li, Yue; Lu, Pengfei; Li, Yaoyao; Gong, Qian; Wang, Shumin

doi:10.1039/c4nr06821a

Cited by 17 publications

(13 citation statements)

References 28 publications

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“…Compared with Si, Ge possesses not only a larger excitonic Bohr radius (24.3 nm) , but also the smaller band gap (0.67 eV), implying that Ge NPs have more prominent quantum confinement effects , and stronger visible photoluminescence . On the basis of the above characteristics, Ge NPs are emerging as promising nanomaterials for potential applications related to solar cells, photodetectors, photothermal therapy, charge storage, bioimaging, and so forth.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Fluorescent and Water-Dispersed Germanium Nanoparticles and Their Cellular Imaging Applications

et al. 2018

Langmuir

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In recent years, Ge nanomaterials have aroused a great deal of attention because of their unique physical and chemical properties. However, the current synthesis methods bear some disadvantages, such as high reaction temperature, dangerous reagents, and inert atmospheres. In this paper, we developed a facile one-step route for preparing fluorescent and water-dispersed germanium nanoparticles (Ge NPs) by utilizing organogermanes as the precursor, operated at mild reactive conditions. The as-synthesized Ge NPs have an average diameter of 2.6 ± 0.5 nm and intense blue-green fluorescence (FL). Furthermore, the as-synthesized Ge NPs show remarkable water dispersibility, favorable biocompatibility, outstanding photostability, excellent storage stability, and low cytotoxicity. More importantly, these Ge NPs can act as a satisfactory FL probe and successfully be applied to cellular imaging of HeLa. The present study offers a simple and moderate strategy for the preparation of Ge NPs and expedites Ge NPs for bioimaging applications.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Fluorescent and Water-Dispersed Germanium Nanoparticles and Their Cellular Imaging Applications

et al. 2018

Langmuir

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“…However, the shift of the conduction band at the L-point is subject to both hydrostatic and shear strain [19], given by …”

Section: Methodsmentioning

confidence: 99%

“…To date, dislocation-free and highly biaxial tensile-strained Ge quantum dots on InP (001) have shown potentials for direct bandgap emitting simulated by finite element method (FEM) [19]. Similar to this, in this work, we theoretically predict morphology of exposed surfaces and growth direction of biaxially tensile-strained GeNWs on a relaxed GaSb template that can be grown directly on Si with an AlSb buffer layer [16, 20].…”

Section: Introductionmentioning

confidence: 95%

Theoretical Investigation of Biaxially Tensile-Strained Germanium Nanowires

et al. 2017

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We theoretically investigate highly tensile-strained Ge nanowires laterally on GaSb. Finite element method has been used to simulate the residual elastic strain in the Ge nanowire. The total energy increment including strain energy, surface energy, and edge energy before and after Ge deposition is calculated in different situations. The result indicates that the Ge nanowire on GaSb is apt to grow along 〈100〉 rather than 〈110〉 in the two situations and prefers to be exposed by {105} facets when deposited a small amount of Ge but to be exposed by {110} when the amount of Ge exceeds a critical value. Furthermore, the conduction band minima in Γ-valley at any position in both situations exhibits lower values than those in L-valley, leading to direct bandgap transition in Ge nanowire. For the valence band, the light hole band maxima at Γ-point is higher than the heavy hole band maxima at any position and even higher than the conduction band minima for the hydrostatic strain more than ∼5.0%, leading to a negative bandgap. In addition, both electron and hole mobility can be enhanced by owing to the decrease of the effective mass under highly tensile strain. The results suggest that biaxially tensile-strained Ge nanowires hold promising properties in device applications.

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“…Due to these properties, an opportunity arises for operation of electronic devices faster at lower applied voltage compared to its chemical analogue Si. Si and Ge are not only chemical analogues but these two elements also demonstrate good partnership in strain engineering using SiGe with higher carrier mobilities (>10.000 cm 2 V −1 s −1 ) which can even lead to the direct band semiconductors upon 1.4 biaxial tensile strain . Recently, electrically pumped lasing and high performance photodetector using Ge on Si were reported.…”

Section: Elemental Analysis Using Eds Measurement and Si–ge Atomic Pementioning

confidence: 99%

Preferential MBE Growth and Characterization of SiGe Nanoislands on Depth‐Selective Si Pits Etched by Ar⁺ Plasma

Seker

Karatutlu

Istengir

2018

Physica Rapid Research Ltrs

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In this study, the size selective deposition of SiGe nanoislands is demonstrated to be possible only in Si nanopits using a molecular beam epitaxy (MBE) system. The depth of the etched Si substrate prepared by Ar+ plasma etching just before the deposition seems to be playing a role in the selectivity of keeping the SiGe nanoislands only inside the nanopits. We observed that, when the thickness of the deposited SiGe layer is around the mean pit depth, which is 4 nm in this case, Ge nucleation takes place selectively on the pre‐etched pits. Relatively larger deposition thickness (e.g., 40 nm) is demonstrated to suppress the preferential growth of the Ge nanocrystals (NCs)/Si NCs which are in return observed all along the surface of the Si substrate. On the other hand, surface migration is considered to play a role in very small depth (relatively more shallow pits) and yielding the unfilled Si nanopits (ca. 1.5 nm) whereas Ge NCs selectively nucleate only within those having larger depths (ca. 3 nm). Such site‐specific 3D controlled growth of nanoislands is shown for the deposition of different semiconductor nanocrystals on top of another for formation of nanodevices fabricated in a single nanopit.

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A new route toward light emission from Ge: tensile-strained quantum dots

Cited by 17 publications

References 28 publications

Synthesis of Fluorescent and Water-Dispersed Germanium Nanoparticles and Their Cellular Imaging Applications

Synthesis of Fluorescent and Water-Dispersed Germanium Nanoparticles and Their Cellular Imaging Applications

Theoretical Investigation of Biaxially Tensile-Strained Germanium Nanowires

Preferential MBE Growth and Characterization of SiGe Nanoislands on Depth‐Selective Si Pits Etched by Ar⁺ Plasma

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A new route toward light emission from Ge: tensile-strained quantum dots

Cited by 17 publications

References 28 publications

Synthesis of Fluorescent and Water-Dispersed Germanium Nanoparticles and Their Cellular Imaging Applications

Synthesis of Fluorescent and Water-Dispersed Germanium Nanoparticles and Their Cellular Imaging Applications

Theoretical Investigation of Biaxially Tensile-Strained Germanium Nanowires

Preferential MBE Growth and Characterization of SiGe Nanoislands on Depth‐Selective Si Pits Etched by Ar+ Plasma

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Preferential MBE Growth and Characterization of SiGe Nanoislands on Depth‐Selective Si Pits Etched by Ar⁺ Plasma