An X-ray photoelectron spectroscopy study of the HF etching of native oxides on Ge(111) and Ge(100) surfaces

Deegan, Terri; Hughes, Greg

doi:10.1016/s0169-4332(97)00511-4

Cited by 110 publications

(78 citation statements)

References 11 publications

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“…27,28 These calculations Raman spectrum of GeH (red) and Ge powder (blue), highlighting the difference in energy of the E2 peak between GeH and Ge (middle inset), as well as a schematic illustration of the A1 and E2 vibrational modes. c) XPS spectrum of the Ge 2p peak for GeH and a Ge(111) wafer with native surface oxide.…”

Section: Synthesis and Structural Characterizationmentioning

confidence: 99%

Stability and Exfoliation of Germanane: A Germanium Graphane Analogue

et al. 2013

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Graphene's success has shown that it is not only possible to create stable, single-atom thick sheets from a crystalline solid, but that these materials have fundamentally different properties than the parent material. We have synthesized for the first time, mm-scale crystals of a hydrogen-terminated germanium multilayered graphane analogue (germanane, GeH) from the topochemical deintercalation of CaGe2. This layered van der Waals solid is analogous to multilayered graphane (CH). The surface layer of GeH only slowly oxidizes in air over the span of 5 months, while the underlying layers are resilient to oxidation based on X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) measurements. The GeH is thermally stable up to 75 o C, however, above this temperature amorphization and dehydrogenation begin to occur. These sheets can be mechanically exfoliated as single and few layers onto SiO2/Si surfaces. This material represents a new class of covalently terminated graphane analogues and has great potential for a wide range of optoelectronic and sensing applications, especially since theory predicts a direct band gap of 1.53 eV and an electron mobility ~five times higher than that of bulk Ge.iii Acknowledgements

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Section: Synthesis and Structural Characterizationmentioning

confidence: 99%

Stability and Exfoliation of Germanane: A Germanium Graphane Analogue

et al. 2013

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“…As for Si, the chemical cleaning of the Ge surface is of the utmost importance for the final device quality. A number of chemicals have been used on the Ge surfaces, such as HF, HNO 3 , HCl, HBr, H 2 O 2 and H 2 O and combinations of some of these [1][2][3][4][5]. It has been reported that HF and H 2 O remove GeO 2 , but not the sub-oxides GeO x , where x < 2, and that HF passivates the Ge surface, limiting reoxidation [2,3], but this is not supported by the results obtained by Choi et al [6].…”

Section: Introductionmentioning

confidence: 99%

The effect of etching on Ge(111) surfaces and Pd Schottky contacts

Nel

Griffiths

Schalkwyk

et al. 2008

Phys. Status Solidi (c)

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The etch rates of various etches and the resulting morphology of the Ge (111) surface have been investigated using atomic force microscopy (AFM) techniques and the oxidation rate of the germanium after etching was monitored by ellipsometry. The effect of the etch on the stability of Pd Schottky barrier diodes (SBDs) was monitored over a period of time using current voltage measurements. It was found that those etches with high etch rates produced much rougher surfaces which in turn showed significant variation in the leakage currents of SBDs deposited on these surfaces. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Such atomically-thin passivation layer on Ge surfaces increases its resistance to oxidation and reduces the surface trap density, thus, contributing the performance improvement of Ge CMOS devices. 5,6 Recently, wide attention has been addressed to wafer-scale growth of graphene, a two-dimensional crystal, on H-terminated Ge(110) surfaces 7 and grafting of molecular layers through liquid-phase self-assembling on atomically flat Ge surfaces, [8][9][10] as it offers an opportunity to achieve new functionality of modern electronic devices, where free-carrier distribution in the near-surface region plays a key role in determining carrier transport and chemical selectivity. Therefore, determination of free-carrier distribution in the near Ge surfaces after different surface treatments has been an important challenge.…”

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confidence: 99%

Distribution of free carriers near heavily-doped epitaxial surfaces of n-type Ge(100) upon HF and HCl treatments

et al. 2015

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Carrier distributions near n-type epitaxially-grown Ge(100) surfaces with high impurity concentrations (1 × 1020 cm−3) were studied using high resolution electron energy loss spectroscopy (HREELS) upon surface treatments in aqueous solutions of HF and HCl. After surface treatments with HCl and HF, the molecular vibration modes distinctly showed either chloride or hydride terminations of Ge surfaces with negligible oxidation. The free-carrier concentration profile was inferred from the conduction band plasmon measurements as a function of the incident electron energies employing a dielectric theory simulation with a 4-layer structure and an effective electron mass of 0.02m0. A carrier-free layer of 40 and 24 Å were derived for HCl- and HF-treated Ge(100), respectively. The surface band bending was estimated to be 0.32 eV for HF-treated Ge. HCl-treated Ge surfaces showed a band bending of 0.91 eV attributed to the strong effect of the surface Cl-Ge dipole.

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An X-ray photoelectron spectroscopy study of the HF etching of native oxides on Ge(111) and Ge(100) surfaces

Cited by 110 publications

References 11 publications

Stability and Exfoliation of Germanane: A Germanium Graphane Analogue

Stability and Exfoliation of Germanane: A Germanium Graphane Analogue

The effect of etching on Ge(111) surfaces and Pd Schottky contacts

Distribution of free carriers near heavily-doped epitaxial surfaces of n-type Ge(100) upon HF and HCl treatments

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