Direct growth of germanium nanowires on glass

Beretta, Sara; Bosi, Matteo; Seravalli, L.; Frigeri, P.; Trevisi, Giovanna; Gombia, E.; Rossi, Francesca; Bersani, Danilo; Ferrari, C.

doi:10.1088/1361-6528/ab9b49

Cited by 3 publications

(5 citation statements)

References 29 publications

(41 reference statements)

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“…Moreover, it is noteworthy to mention that even though Ge NWs grown for this study are nominally undoped, it is well known that the presence of acceptor-like trap levels on Ge NW gives rise to the hole accumulation at the surface of NW [ 29 – 31 ]. In support to this hypothesis, in our previous investigations we observed that single Ge NW, obtained under the same growth conditions of NW structures studied in this work and contacted by focused ion beam (FIB)-deposited platinum [ 25 ], showed a p-type field effect behaviour. As a consequence, the semiconductor–metal contact formation at the electrodes and the conduction mechanisms through NW networks can be properly discussed assuming the p-type character for Ge NWs .…”

Section: Resultssupporting

confidence: 83%

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Electrical properties and chemiresistive response to 2,4,6 trinitrotoluene vapours of large area arrays of Ge nanowires

et al. 2023

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We study the electrical and morphological properties of random arrays of Ge nanowires (NW) deposited on sapphire substrates. NW-based devices were fabricated with the aim of developing chemiresistive-type sensors for the detection of explosive vapours. We present the results obtained on pristine and annealed NWs and, focusing on the different phenomenology observed, we discuss the critical role played by NW–NW junctions on the electrical conduction and sensing performances. A mechanism is proposed to explain the high efficiency of the annealed arrays of NWs in detecting 2,4,6 trinitrotoluene vapours. This study shows the promising potential of Ge NW-based sensors in the field of civil security.

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Section: Resultssupporting

confidence: 83%

“…Ge nanowires were grown using an Au-catalysed chemical vapour deposition process with no intentional doping. Details of Metal Organic Vapour Phase Epitaxy (MOVPE) technique can be found in earlier works [ 24 , 25 ]. Crystalline as-grown nanowires have diameters ranging from 70 to 90 nm and lengths up to 30 µm.…”

Section: Methods/experimentalmentioning

confidence: 99%

Electrical properties and chemiresistive response to 2,4,6 trinitrotoluene vapours of large area arrays of Ge nanowires

et al. 2023

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“…In order to validate the simulation of properties of Ge NWs modeled as discussed above, as a first step we carried on a calculation considering the nanostructures characterized in [ 32 ]. Hence, we calculated the I–V characteristic for a Ge NW with same morphological properties (95 nm diameter, 9.6 µm length) and with electrical contacts 2 µm long on both sides of the NW.…”

Section: Model Detailsmentioning

confidence: 99%

“…We run the same simulation for different voltage biases applied to the contacts at the end of the NW, aiming to derive the I–V characteristic in the range between 0 and 0.1 V. The results are shown in Figure 3 , where they are plotted against the experimental data taken from [ 32 ].…”

Section: Model Detailsmentioning

confidence: 99%

Germanium Nanowires as Sensing Devices: Modelization of Electrical Properties

2021

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In this paper, we model the electrical properties of germanium nanowires with a particular focus on physical mechanisms of electrical molecular sensing. We use the Tibercad software to solve the drift-diffusion equations in 3D and we validate the model against experimental data, considering a p-doped nanowire with surface traps. We simulate three different types of interactions: (1) Passivation of surface traps; (2) Additional surface charges; (3) Charge transfer from molecules to nanowires. By analyzing simulated I–V characteristics, we observe that: (i) the largest change in current occurs with negative charges on the surfaces; (ii) charge transfer provides relevant current changes only for very high values of additional doping; (iii) for certain values of additional n-doping ambipolar currents could be obtained. The results of these simulations highlight the complexity of the molecular sensing mechanism in nanowires, that depends not only on the NW parameters but also on the properties of the molecules. We expect that these findings will be valuable to extend the knowledge of molecular sensing by germanium nanowires, a fundamental step to develop novel sensors based on these nanostructures.

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“…Many nanowire synthesis methods have been proposed and intensively studied, − to obtain desired nanowire structures at high precision and efficiency. In particular, the VLS method, as one of the bottom-up synthesis routes, has realized a variety of new materials and morphologies including Ge NWs, with good control over the material’s physical and chemical properties. − A typical VLS process for catalyzed semiconductor growth can be described as follows: a heated metal catalyst and the gaseous precursor first form a liquid alloy, which has a high adhesion capacity to facilitate further material absorption from the gas phase. When the supersaturated state of the liquid is reached, the target material is extracted and then deposits on the liquid–solid interface, leading to a bottom-up continuous growth of the wire.…”

Section: Introductionmentioning

confidence: 99%

Revealing Atomistic Mechanisms of Gold-Catalyzed Germanium Growth Using Molecular Dynamics Simulations

Wang

2022

J. Phys. Chem. C

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The vapor−liquid−solid (VLS) method is considered a plausible technique for synthesizing germanium (Ge) nanostructures (e.g., nanowires), which have a broad range of applications due to their unique electronic properties and intrinsic compatibility with silicon. However, crystallization failures and material defects are still frequently observed in VLS processes, with insufficient understanding of their underlying mechanisms due to instrumental limitations for high-resolution in situ characterizations. Employing an accurate interatomic potential well fitted to the gold−germanium (Au−Ge) phase diagram, we performed molecular dynamics simulations for a systematic investigation of the Au-catalyzed growth process of Ge crystals. From the simulations, relationships were established between the overall Ge growth rate and several main synthesis conditions, including substrate crystallographic orientation, temperature, and Ge supersaturation in liquid. The dynamical behaviors of Ge atoms near the liquid−solid growing interface were captured, from which the atom surface stability and exchange rate were estimated for quantifying the atomistic details of the growth. These interface properties were further linked to the surface morphologies, to explain the observed orientation-dependent growing modes. This study sheds new light on the understanding of the VLS growth mechanisms of Ge crystals and provides scientific guidelines for designing innovative synthesis methods for similar nanomaterials.

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Direct growth of germanium nanowires on glass

Cited by 3 publications

References 29 publications

Electrical properties and chemiresistive response to 2,4,6 trinitrotoluene vapours of large area arrays of Ge nanowires

Electrical properties and chemiresistive response to 2,4,6 trinitrotoluene vapours of large area arrays of Ge nanowires

Germanium Nanowires as Sensing Devices: Modelization of Electrical Properties

Revealing Atomistic Mechanisms of Gold-Catalyzed Germanium Growth Using Molecular Dynamics Simulations

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