Micro-Raman analysis of quantum confined crystalline germanium nanowire arrays

McCarthy, John P.; Audoit, G.; Perova, T. S.; Moore, Robert A.; Holmes, Justin D.; Morris, Michael A.

doi:10.1784/insi.2006.48.12.735

Cited by 2 publications

(2 citation statements)

References 13 publications

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“…The asymmetry of the peak is caused by a low frequency shoulder, which was identified after deconvolution, as the TO peak of amorphous germanium with a maximum at 275 cm -1 and full width at half maximum (FWHM) of 32 cm -1 . Such asymmetrical broadening and shift of TO peak were already predicted and established by several authors (13)(14)(15). The value of the FWHM of TO peak of crystalline germanium seems to be high (15 cm -1 ), however, in very thin NWs (10 nm and less) as in our case quantum confinement phenomena should be taken into account.…”

Section: Resultssupporting

confidence: 82%

Deposition of Germanium Nanowires from Digermane Precursor: Influence of the Substrate Pretreatment

Dřı́nek¹,

Fajgаr²,

Klementová³

et al. 2009

ECS Trans.

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Germanium Nanowires (GeNWs) were synthesized by Low Pressure Chemical Vapor Deposition (LPCVD) of hexamethyldigermane (GeMe3)2 at temperature of 490 {degree sign}C and pressure of 90-100 Pa. GeNWs of several nanometers in diameter and a few microns in length were deposited onto various substrates - stainless steel, Fe, Mo, Ta, W, Si, and SiO2. Influence of surface pretreatment of the substrates (roughening of surface or Ge sputtering) is discussed in respect to the previously published theory of GeNW growth through the intermetallic alloy mechanism. The results conclude that another mechanism should be taken into account - the non-catalyst mechanism. Ge seeds necessary for triggering GeNW growth are formed by aggregation of Ge atoms/atom clusters/fragments which are stuck onto the substrate surface at the beginning of the process. The non-catalyst growth of GeNW triggered by such mechanism can be applied in growing GeNWs on semiconductors and insulators.

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Section: Resultssupporting

confidence: 82%

Deposition of Germanium Nanowires from Digermane Precursor: Influence of the Substrate Pretreatment

Dřı́nek¹,

Fajgаr²,

Klementová³

et al. 2009

ECS Trans.

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“…Such asymmetrical broadening and shift of the TO peak were already predicted and established by several authors. [16][17][18] The value of the fwhm of the TO peak of crystalline germanium seems to be high ͑15 cm −1 ͒; however, in very thin NWs ͑10 nm and less͒ as in our case, quantum confinement phenomena should be taken into account. In addition, the Raman spectra show typical D and G peaks at 1361 and 1588 cm −1 , respectively.…”

Section: Resultsmentioning

confidence: 52%

Deposition of Germanium Nanowires from Hexamethyldigermane: Influence of the Substrate Pretreatment

Dřı́nek

Fajgаr

Klementová

et al. 2010

J. Electrochem. Soc.

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Germanium nanowires ͑GeNWs͒ were synthesized by low pressure chemical vapor deposition of hexamethyldigermane ͑GeMe 3 ͒ 2 at 490°C and a pressure of 90-100 Pa. GeNWs of several nanometers in diameter and a few micrometers in length were deposited onto substrates made of stainless steel, Fe, Mo, Ta, W, Si, and SiO 2 . The influence of surface pretreatment of the substrates ͑roughening of surface, grooves made by a diamond tip or Ge thermal evaporation͒ is discussed. GeNW deposits were studied using scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared, Raman spectroscopy, and energy-dispersive X-ray analyses.Nowadays, the progress in microelectronics has been driven by nanoscale technology for two-and one-dimensional structures. Therefore, nano-objects ͓nanowires ͑NWs͒, nanotubes, nanorods, nanopillars, nanoribbons, etc.͔ made of novel materials and alloys with unique properties have been studied and tested in detail in microelectronic systems. Gradually, such nano-objects are implemented into silicon technology to update and enhance the power and efficiency of microelectronic circuits, solar cell arrays, catalyst systems, etc.Germanium is considered to replace silicon in some applications as it has a higher electron and hole mobility ͑3900 and 1900 cm 2 /V s, respectively͒ than silicon ͑1500 and 450 cm 2 /V s, respectively͒. Moreover, the Bohr radius of germanium is larger ͑24.3 vs 4.3 nm for silicon͒ and, therefore, quantum phenomena are more readily established. 1 Field emission transistors using germanium nanowires ͑GeNWs͒ have already been reported. [2][3][4] The most commonly used methods for the preparation of GeNWs are the vapor-liquid-solid ͑VLS͒ technique and the seedassisted deposition processes using catalyst nanoparticles ͑mostly Au͒. 5-7 However, the seeds act as traps for free charge carriers and therefore shorten their lifetime. The seed atoms could also migrate through the circuit structure and degrade its electronic properties. Although some attempts were made to manufacture NW microelectronic structures using Au seed nanocolloids, 8,9 the whole manufacturing process is complicated by the steps of introducing and removing Au nanoparticles from the fabricated NW structure.A solution to this problem is based on a noncatalyst process that avoids using heteroatom seeds. Some of them seem not to be convenient for standard microelectronic arrays because they anticipate other chemicals as in electrochemical etching applying a HClcontaining aqueous electrolyte. 10 The best results of the noncatalyst growth of GeNWs have been obtained by chemical vapor deposition ͑CVD͒ procedures.The first approach relates to the idea of intermetallic sites serving as initial centers of GeNW growth. Mathur et al. 11 proposed an intermetallic concept of the self-catalyst initial stage of GeNWs grown onto iron substrates. They assumed the formation of Fe-Ge intermetallic nuclei on an iron substrate durin...

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Micro-Raman analysis of quantum confined crystalline germanium nanowire arrays

Cited by 2 publications

References 13 publications

Deposition of Germanium Nanowires from Digermane Precursor: Influence of the Substrate Pretreatment

Deposition of Germanium Nanowires from Digermane Precursor: Influence of the Substrate Pretreatment

Deposition of Germanium Nanowires from Hexamethyldigermane: Influence of the Substrate Pretreatment

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