Formation and characterization of varied size germanium nanocrystals by electron microscopy, Raman spectroscopy, and photoluminescence

Ou, Haiyan; Ou, Yiyu; Liu, Chuan; Berg, Rolf W.; Rottwitt, Karsten

doi:10.1364/ome.1.000643

Cited by 14 publications

(24 citation statements)

References 33 publications

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“…CVD techniques like PECVD and LPCVD can also be used to fabricate Ge‐rich layers. These methods are very flexible and were used to deposit either thick layers or superlattice structures . However, the deposition process requires toxic, explosive, and expensive gases like monosilane, monogermane, methane, and hydrogen.…”

Section: Synthesis Of Ge Nanocrystals Via Phase Separation From Supermentioning

confidence: 99%

“…The origin of these bands is controversially discussed. The signal is either attributed to confined carrier recombination inside the nanocrystals or defect states . Defects can be located in the matrix, e.g., due to oxygen vacancies or at the interface between nanocrystals and the matrix .…”

Section: Influence Of Different Matrix Materialsmentioning

confidence: 99%

“…These methods are very flexible and were used to deposit either thick layers [47,48] structures. [49][50][51][52] However, the deposition process requires toxic, explosive, and expensive gases like monosilane, monogermane, methane, and hydrogen. An important parameter that determines the germanium concentration of the film is the flux of the precursor.…”

Section: Chemical Vapor Deposition (Cvd)mentioning

confidence: 99%

See 2 more Smart Citations

A Review on Ge Nanocrystals Embedded in SiO₂ and High‐k Dielectrics

Lehninger

Beyer

Heitmann

2018

Physica Status Solidi (a)

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In this article, the work on Ge nanocrystals embedded in dielectric films formed by phase separation from supersaturated solid solutions is reviewed. Different methods to synthesize supersaturated solid solutions are covered, e.g., magnetron sputtering, ion implantation, and chemical vapor deposition. The phase separation is activated by subsequent high temperature annealing. Important parameters that influence the formation and properties of the Ge nanocrystals are discussed. Various matrix materials like SiO2, Al2O3, HfO2, HfAlOx, Lu2O3, ZrO2, TaZrOx, and Si3N4 are reported in the literature. The influence of the matrix on the formation and properties of the Ge nanocrystals is addressed in this review. Ge nanocrystals are investigated for applications such as charge storage nodes in nonvolatile memory devices or as silicon technology compatible light emitters. A key to establish these applications seems to be embedding the Ge nanocrystals in still amorphous matrices. This could help to avoid grain boundaries that act as leakage paths for electrical charges (unfavorable for nonvolatile memories) and facilitate defects, which could act as recombination centers (unfavorable for light emitters). A further important point is the synthesis of size and position controlled Ge nanocrystals. Both aspects are reviewed for Ge nanocrystals embedded in the mentioned matrix materials.

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Section: Synthesis Of Ge Nanocrystals Via Phase Separation From Supermentioning

confidence: 99%

Section: Influence Of Different Matrix Materialsmentioning

confidence: 99%

Section: Chemical Vapor Deposition (Cvd)mentioning

confidence: 99%

See 1 more Smart Citation

A Review on Ge Nanocrystals Embedded in SiO₂ and High‐k Dielectrics

Lehninger

Beyer

Heitmann

2018

Physica Status Solidi (a)

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“…11) spectral range. However, also defects in the matrices [46,47], radiative transitions at the interfaces between nanocrystals and matrix [33][34][35][36] and GeO 2 interface defects [48] are discussed as possible origins, especially for luminescence bands near the high-energy peak. All spectra consist of two well distinguishable PL peaks at about 2.2 eV (low-energy peak) and 2.9 eV (high-energy peak).…”

Section: Optical Properties Of Ge Nanocrystals Embedded In Zro 2 and mentioning

confidence: 99%

Size and Shape Controlled Semiconductor Nanocrystals Synthesized by RF‐Sputtering Techniques for Electronic and Optoelectronic Applications

Lehninger

Beyer

Schneider

et al. 2015

Contrib. Plasma Phys.

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Group IV (Ge and Si) nanocrystals embedded in a dielectric matrix were prepared via rf magnetron sputtering by the deposition of superlattices of stoichiometric and substoichiometric oxide layers and subsequent annealing. By this way Ge nanocrystals in a (Ta)ZrO x and Si nanocrystals in an SiO2 matrix were prepared in a size and shape controlled manner. In case of the Ge-ZrO2 system, elongated Ge nanocrystals in a crystallized ZrO2 matrix were formed for annealing temperatures above 660 • C. Starting from a Si3N4 interface of the Si wafer, a preferential orientation between the Ge and ZrO2 lattice can be stated. Doping the ZrO2 matrix additionally with Ta increases the crystallization temperature of the ZrO2 matrix and leads to the formation of Ge nanocrystals embedded in an amorphous TaZrOx matrix. The Ge nanocrystals were investigated by photoluminescence measurements and implemented into metal-insulator-semiconductor capacitor to investigate their potential for charge trapping devices. The prepared nano floating gate devices show good charging characteristics with a maximum memory window of 5 V and a slope of the writing voltage vs. memory window characteristics of 0.8-1. All luminescence centers seen in the Ge-(Ta)ZrOx system can be attributed to defects either from the Ge nanocrystal surface, the (Ta)ZrOx matrix or the Si substrate itself. Si nanocrystals were fabricated in the same way in an amorphous SiO2 film after annealing above 900 • C. The formed Si nanocrystals act as superior sensitizer for Er 3+ ions which were ion implanted into the films followed by an additional subsequent anneal, varied between 700 and 1000 • C. The Si nanocrystal -Er 3+ system was successfully implemented into a slot waveguide structure showing a strong polarization dependent field enhancement in both emission and excitation geometry.

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“…Bottom-up synthesis methods can effectively assemble small molecule precursors into larger units to create small NPs. [22][23][24][25][26][27][28][29][30][31][32][33][34][35] However, both methods require harsh chemicals [20,34] or specialized equipment, [13,21,27,29,35] out of reach from many end users. Ideally, one could obtain extremely monodisperse NPs of small size and high yield on regular benchtop equipment on site.We here propose a top-down method of NP synthesis that results in high-monodispersity NPs.…”

mentioning

confidence: 99%

Sonofragmentation of Ultrathin 1D Nanomaterials

Gao

Gupta

Boyden

2016

Part. Part. Syst. Charact.

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A simple strategy for making nanoparticles by sonofragmentation of high-aspect-ratio 1D substrates is introduced. With common laboratory equipment, ultra-thin nanowires are fragmented into nanoparticles of size determined by the nanowire width, resulting within hours in monodisperse, crystalline nanoparticles of < 10 nm. This strategy is applicable to a diversity of semiconductor, oxide and metal nanowires.

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Formation and characterization of varied size germanium nanocrystals by electron microscopy, Raman spectroscopy, and photoluminescence

Cited by 14 publications

References 33 publications

A Review on Ge Nanocrystals Embedded in SiO₂ and High‐k Dielectrics

A Review on Ge Nanocrystals Embedded in SiO₂ and High‐k Dielectrics

Size and Shape Controlled Semiconductor Nanocrystals Synthesized by RF‐Sputtering Techniques for Electronic and Optoelectronic Applications

Sonofragmentation of Ultrathin 1D Nanomaterials

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Formation and characterization of varied size germanium nanocrystals by electron microscopy, Raman spectroscopy, and photoluminescence

Cited by 14 publications

References 33 publications

A Review on Ge Nanocrystals Embedded in SiO2 and High‐k Dielectrics

A Review on Ge Nanocrystals Embedded in SiO2 and High‐k Dielectrics

Size and Shape Controlled Semiconductor Nanocrystals Synthesized by RF‐Sputtering Techniques for Electronic and Optoelectronic Applications

Sonofragmentation of Ultrathin 1D Nanomaterials

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A Review on Ge Nanocrystals Embedded in SiO₂ and High‐k Dielectrics

A Review on Ge Nanocrystals Embedded in SiO₂ and High‐k Dielectrics