Passivation and Characterization of Germanium Surfaces

Amy, Sandrine Rivillon; Chabal, Yves J.

doi:10.1007/978-3-540-71491-0_4

Cited by 15 publications

(23 citation statements)

References 67 publications

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“…14,17 At negative potentials, two absorption peaks observed at 1990 cm À1 and 2015 cm À1 were assigned to stretching modes from GeH and GeH 2 groups, respectively. 17 This assignment was based on the data gathered under vacuum conditions, 28 and agrees with the results from force field calculations. 29 To describe the full series of spectra completely and assign the different peaks observed on both Ge surfaces, at least three different components are required, centred around B2025-2030 cm À1 ( ), B2000-2015 cm À1 ( ) and B1977-1990 cm À1 ( ), with minor differences in maxima between Ge(100) and Ge(111) surfaces (see above).…”

Section: Post-mortem Surface Analysissupporting

confidence: 74%

Mechanism of the potential-triggered surface transformation of germanium in acidic medium studied by ATR-IR spectroscopy

Nayak

Erbe

2016

Phys. Chem. Chem. Phys.

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In acidic solution, germanium surfaces undergo a transformation to hydrogen-terminated surfaces at sufficiently negative electrode potentials. Herein, we used in situ and operando attenuated total reflection infrared (ATR-IR) spectroscopy coupled to electrochemical experiments to study the details of this surface transformation on Ge(111) and Ge(100) in 0.1 M HClO. The ATR-IR data gathered during the surface transformation are consistent with an interpretation according to which an intermediate state exists of a surface with mixed termination. In the mixed termination, both H and OH are bound to the surface, which showed a Ge-H stretching mode at ∼2025-2030 cm. At sufficiently negative potentials, the surfaces became fully hydrogen terminated. ATR-IR spectra can be understood by assigning the peak at ∼1977-1990 cm to the stretching mode of GeH species on Ge(111), and the peak at ∼2000-2015 cm to a stretching mode of GeH species on Ge(100). Measurements of the linear dichroism showed the GeH species to be oriented predominantly upright. The transition dipole moment of the GeH species was oriented parallel to the surface, as expected for an antisymmetric stretching mode.

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Section: Post-mortem Surface Analysissupporting

confidence: 74%

Mechanism of the potential-triggered surface transformation of germanium in acidic medium studied by ATR-IR spectroscopy

Nayak

Erbe

2016

Phys. Chem. Chem. Phys.

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“…43,44,45 Under these aqueous conditions, the laborious and hazardous pre-treatment with aqueous HF is not needed, as the Ge oxide at the surface is water soluble. 46 The chemical grafting of diazonium salts All these modified surfaces were then characterized by contact angle measurements and the results were compared to those obtained with bare surfaces (i.e., surfaces that were treated similarly to the modified ones but in the absence of the diazonium salt). Contact angles of 62 ± 9° and 30 ± 10° were obtained respectively for bare Au and Ge substrates ( Table 1).…”

Section: Resultsmentioning

confidence: 99%

Grafting of Oligo(ethylene glycol)-Functionalized Calix[4]arene-Tetradiazonium Salts for Antifouling Germanium and Gold Surfaces

et al. 2018

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Biosensors that can determine protein concentration and structure are highly desired for biomedical applications. For the development of such biosensors, the use of Fourier transform infrared (FTIR) spectroscopy with the attenuated internal total reflection (ATR) configuration is particularly attractive, but it requires appropriate surface functionalization of the ATR optical element. Indeed, the surface has to specifically interact with a target protein in close contact with the optical element and must display antifouling properties to prevent nonspecific adsorption of other proteins. Here, we report robust monolayers of calix[4]arenes bearing oligo(ethylene glycol) (oEG) chains, which were grafted on germanium and gold surfaces via their tetradiazonium salts. The formation of monolayers of oEGylated calix[4]arenes was confirmed by AFM, IR, and contact angle measurements. The antifouling properties of these modified surfaces were studied by ATR-FTIR spectroscopy and fluorescence microscopy, and the nonspecific absorption of bovine serum albumin was found to be reduced by 85% compared to that of unmodified germanium. In other words, the organic coating by oEGylated calix[4]arenes provides remarkable antifouling properties, opening the way for the design of germanium- or gold-based biosensors.

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“…Higher annealing temperatures (>450 C) results in the desorption of GeO to produce an almost oxide-free surface 35,37 with some residual Ge 3+ still present at 500 C. 37 The presence of water vapour greatly accelerates the rate of Ge oxidation, 38 as does exposure to UV light producing predominately GeO 2 . 39 Prolonged ambient exposure (60 days) of Ge nanowires results in the disappearance of the Ge 1+ oxidation state and the formation of a predominately Ge 4+ oxide. 40 The oxidation behaviour of Ge nanowires is also dependent on the dopant type; 41 ambient exposure for 2 min after annealing of p-type Ge nanowires resulted in the rapid formation of GeO, followed by the slower formation of GeO 2 over a few hours.…”

Section: Oxidation Of Ge Nanowiresmentioning

confidence: 99%

Chemical functionalisation of silicon and germanium nanowires

Collins

Holmes

2011

J. Mater. Chem.

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The reduced dimensionality of nanowires implies that surface effects significantly influence their properties, which has important implications for the fabrication of nanodevices such as field effect transistors and sensors. This review will explore the strategies available for wet chemical functionalisation of silicon (Si) and germanium (Ge) nanowires. The stability and electrical properties of surface modified Si and Ge nanowires is explored. While this review will focus primarily on nanowire surfaces, much has been learned from work on planar substrates and differences between 2D and nanowire surfaces will be high-lighted. The possibility of band gap engineering and controlling electronic characteristics through surface modification provides new opportunities for future nanowire based applications. Nano-sensing is emerging as a major application of modified Si nanowires and the progress of these devices to date is discussed.

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Passivation and Characterization of Germanium Surfaces

Cited by 15 publications

References 67 publications

Mechanism of the potential-triggered surface transformation of germanium in acidic medium studied by ATR-IR spectroscopy

Mechanism of the potential-triggered surface transformation of germanium in acidic medium studied by ATR-IR spectroscopy

Grafting of Oligo(ethylene glycol)-Functionalized Calix[4]arene-Tetradiazonium Salts for Antifouling Germanium and Gold Surfaces

Chemical functionalisation of silicon and germanium nanowires

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