Structure of Si(111) surfaces etched in 40% NH4F: Influence of the doping

Roche, Jason; Ramonda, Michel; Thibaudau, F.; Dumas, Ph.; Mathiez, P.; Salvan, F.; Allongue, Philippe

doi:10.1051/mmm:0199400504-6029100

Cited by 13 publications

(5 citation statements)

References 15 publications

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“…We note, however, that the broader Si 2p and C 1s peaks observed for the HDp Si adsorbed monolayers (Figure a and c, respectively) are a result of the unusual structural and chemical properties of the freshly etched HDp Si surface. It has been shown that such surfaces are much rougher, compared to the n-Si surface, and that they are not always H-terminated. − As a result, this Si–C interface is not as well ordered or defined as that for other Si doping levels. For further characterization of the HDp samples, see the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

Effect of Doping Density on the Charge Rearrangement and Interface Dipole at the Molecule–Silicon Interface

et al. 2013

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The interface level alignment of alkyl and alkenyl monolayers, covalently bound to oxide-free Si substrates of various doping levels, is studied using X-ray photoelectron spectroscopy. Using shifts in the C 1s and Si 2p photoelectron peaks as a sensitive probe, we find that charge distribution around the covalent Si–C bond dipole changes according to the initial position of the Fermi level within the Si substrate. This shows that the interface dipole is not fixed but rather changes with the doping level. These results set limits to the applicability of simple models to describe level alignment at interfaces and show that the interface bond and dipole may change according to the electrostatic potential at the interface.

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Section: Resultsmentioning

confidence: 99%

Effect of Doping Density on the Charge Rearrangement and Interface Dipole at the Molecule–Silicon Interface

et al. 2013

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“…Therefore, medium-doped samples had to be used for the IR studies. 39,42,43 The current-voltage (I-V) isotherms, I-V-T curves, for a Si-(CH 2 ) 17 CH 3 (C18) monolayer/Hg junction are shown in Fig. 2a.…”

Section: Resultsmentioning

confidence: 99%

Structure Matters: Correlating temperature dependent electrical transport through alkyl monolayers with vibrational and photoelectron spectroscopies

et al. 2012

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Freezing out of molecular motion and increased molecular tilt enhance the efficiency of electron transport through alkyl chain monolayers that are directly chemically bound to oxide-free Si. As a result, the current across such monolayers increases as the temperature decreases from room temperature to $80 K, i.e., opposite to thermally activated transport such as hopping or semiconductor transport. The 30-fold change for transport through an 18-carbon long alkyl monolayer is several times the resistance change for actual metals over this range. FTIR vibrational spectroscopic measurements indicate that cooling increases the packing density and reduces the motional freedom of the alkyl chains by first stretching the chains and then gradually tilting the adsorbed molecules away from the surface normal. Ultraviolet photoelectron spectroscopy shows drastic sharpening of the valence band structure as the temperature decreases, which we ascribe to decreased electron-phonon coupling. Although conformational changes are typical in soft molecular systems, in molecular electronics they are rarely observed experimentally or considered theoretically. Our findings, though, indicate that the molecular conformational changes are a prominent feature, which imply behavior that differs qualitatively from that described by models of electronic transport through inorganic mesoscopic solids.

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“…The immersion times and temperatures are (b) 480 min, 5 °C, (c) 240 min, 63 °C, and (d) 60 min, 81 °C. White lines forming a triangle, added to (b), indicate the 〈1̄1̄2〉 direction and equivalents of the Si(111) surface, determined from the directions of trigonal etch pits whose edges are known to be in parallel to the 〈1̄1̄2〉 direction or equivalents. , …”

Section: Resultsmentioning

confidence: 99%

Temperature Dependence of Formation of Nanorods and Dots of Iodine Compounds on an H-Terminated Si(111) Surface in a Concentrated HI Solution

2004

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Immersion of atomically flat, H-terminated Si(111) surfaces in 7.6 M HI for 0.5 - 4 h caused spontaneous formation of nanosized clusters at the Si surface. X-ray photoelectron spectroscopy analysis suggested that the clusters were composed of silicon iodides (such as SiHxI4-x), produced most probably by Si etching with HI. Atomic force microscopy inspection revealed that the immersion at a low temperature below about 30 degrees C led to the formation of long rod-shaped clusters, oriented in the (112) direction or equivalents, whereas the immersion at a high temperature above 30 degrees C led to the formation of circular dot clusters, their size and shape changing abruptly at about 70 degrees C. It is shown experimentally that the formation of dot clusters at a high immersion temperature is explained on the basis of thermodynamics, whereas that of oriented rod clusters at a low temperature is explained by a kinetics-controlled mechanism.

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Structure of Si(111) surfaces etched in 40% NH4F: Influence of the doping

Cited by 13 publications

References 15 publications

Effect of Doping Density on the Charge Rearrangement and Interface Dipole at the Molecule–Silicon Interface

Effect of Doping Density on the Charge Rearrangement and Interface Dipole at the Molecule–Silicon Interface

Structure Matters: Correlating temperature dependent electrical transport through alkyl monolayers with vibrational and photoelectron spectroscopies

Temperature Dependence of Formation of Nanorods and Dots of Iodine Compounds on an H-Terminated Si(111) Surface in a Concentrated HI Solution

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