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Morphology, Chemical Composition, and Defect Evolution During Synthesis and Annealing of Core/Shell Germanium/Germanium-Tin Nanowires.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Morphology, Chemical Composition, and Defect Evolution During Synthesis and Annealing of Core/Shell Germanium/Germanium-Tin Nanowires./
作者:	Braun, Michael.
面頁冊數:	1 online resource (162 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-01, Section: B.
Contained By:	Dissertations Abstracts International84-01B.
標題:	By products. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29176530click for full text (PQDT)
ISBN:	9798835546244

Morphology, Chemical Composition, and Defect Evolution During Synthesis and Annealing of Core/Shell Germanium/Germanium-Tin Nanowires.
Braun, Michael.

Morphology, Chemical Composition, and Defect Evolution During Synthesis and Annealing of Core/Shell Germanium/Germanium-Tin Nanowires. - 1 online resource (162 pages)

Source: Dissertations Abstracts International, Volume: 84-01, Section: B.

Thesis (Ph.D.)--Stanford University, 2022.

Includes bibliographical references

Moore's law, the continual decrease in transistor size, has marched on for roughly fifty years, during which time many fabrication challenges have been overcome. Limitations in current fabrication techniques, such as diffraction and suitable light sources, are being approached. Currently, transistors are fabricated in a "top-down" fashion, via photolithography patterning and etching of large wafers. In addition to fabrication challenges, quantum effects are becoming increasingly important due to the size scale of current devices. A significant research interest outlined by the International Technology Roadmap for Semiconductors for end-of-roadmap Metal-Oxide-Semiconductor (MOS) devices, such as transistors, is the advancement of nanowire technology. In contrast to current "top-down" fabrication, nanowires can be grown in a "bottom up" fashion, often from nanoscale catalysts dispersed on the surface of a substrate. A common growth mechanism is the vapor-liquid-solid (VLS) mechanism, where a vapor of the desired wire material is injected into a reactor, with a liquid catalyst sitting on top of a solid, growing nanowire. In addition to the promise for continuously increasing transistor density on computer chips, nanowire structures provide a platform for fundamental research. Due to the inherent nano-scale diameter and large aspect ratio, nanowires demonstrate structureproperty relationships that often differ from those of bulk materials, including dimensional confinement of electronic carriers and light, a large surface area to volume ratio, and sizeand shape-dependent partitioning of mechanical strain and barriers to inelastic deformation. Because of these characteristics, there is growing interest in nanowires for applications such as lasers, field effect transistors, and photodetectors. First, a technique using in-situ laser reflectometry was investigated for measuring the axial growth rate in chemical vapor deposition of assemblies of well-aligned vertical germanium nanowires grown epitaxially on single crystal substrates. Finite difference frequency domain optical simulations were performed to facilitate quantitative analysis and interpretation of the measured reflectivity data. The results showed an insensitivity of reflected intensity oscillation period to nanowire diameter and density within the range of experimental conditions investigated. Compared to previous quantitative in-situ measurements performed on III-V nanowire arrays, which showed two distinct rate regimes, we observed a constant, steady-state wire growth rate. Furthermore, we showed that the measured reflectivity decay can be used to determine the germanium nanowire nucleation time with good precision. This technique provides an avenue to monitor growth of nanowires in a variety of materials systems and growth conditions. The link between the optical emission and atomic structure of individual vertical Ge/GeSn core/shell nanowires was investigated using transmission electron microscopy (TEM) and cathodoluminescence (CL). Optical measurements of individually as-grown nanowires were performed using scanning electron microscopy (SEM) CL. Electron beam deposited fiducial markers were utilized to identify and track individual nanowires between CL measurements and focused ion beam preparation for TEM analysis. High angle annular dark field scanning TEM (HAADF STEM) was then performed as a probe into the origin of the non-homogeneous CL emission between the identified nanowires based on observable line defects. Although statistically limited due to the nature of TEM, the brightness variations were consistent with expected trends of total defects and volume of defect-free material.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798835546244Subjects--Topical Terms:

3564729
By products.
Index Terms--Genre/Form:

542853
Electronic books.

Morphology, Chemical Composition, and Defect Evolution During Synthesis and Annealing of Core/Shell Germanium/Germanium-Tin Nanowires.
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504 $a Includes bibliographical references
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