Capacitance of a molecular overlayer on the silicon surface measured by scanning tunneling microscopy

Akiyama, Ryota; Matsumoto, Takuya; Kawai, Tomoji

doi:10.1103/physrevb.62.2034

Cited by 32 publications

(25 citation statements)

References 16 publications

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“…Clean Si(001) surfaces (1-10 ohm cm resistivity, B-doped) were prepared by a published method. [11] . Acetone (Aldrich, 99.9 + % purity) was subjected to several freeze-pump-thaw cycles prior to introduction into the UHV chamber.…”

Section: Methodsmentioning

confidence: 95%

Kinetic and Thermodynamic Control by Chemical Bond Rearrangement on a Si(001) Surface

et al. 2004

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Section: Methodsmentioning

confidence: 95%

Kinetic and Thermodynamic Control by Chemical Bond Rearrangement on a Si(001) Surface

et al. 2004

Self Cite

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“…The experimentally measured values of the height and relative permittivity of cyclopentene are 5 Å and 1.26, respectively (40). Plugging these values and the expression for Z gap from Eq.…”

Section: Resultsmentioning

confidence: 99%

“…The STM control software allows for changes in the tip position (⌬Z) relative to the initial tip-sample distance (Z 0 ) that is determined by the setpoint conditions of 0.1-nA tunneling current and Ϫ2-V sample bias. On the basis of the 10-Å value of the tip-sample spacing estimated from the current-voltage curve on the clean Si(100) surface, the measured 1-Å height of the cyclopentene molecule, and the known 5-Å actual height of cyclopentene (40), the value of Z 0 when the tip is positioned over a cyclopentene molecule is estimated to be Ϸ6 Å. Consequently, for variable tip-sample spacing measurements on cyclopentene, we assume:…”

Section: Resultsmentioning

confidence: 99%

Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy

Guisinger

Yoder

Hersam

2005

Proc. Natl. Acad. Sci. U.S.A.

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A cryogenic variable-temperature ultra-high vacuum scanning tunneling microscope is used for measuring the electrical properties of isolated cyclopentene molecules adsorbed to the degenerately p-type Si(100)-2؋1 surface at a temperature of 80 K. Currentvoltage curves taken under these conditions show negative differential resistance at positive sample bias, in agreement with previous observations at room temperature. Because of the enhanced stability of the scanning tunneling microscope at cryogenic temperatures, repeated measurements can be routinely taken over the same molecule. Taking advantage of this improved stability, we show that current-voltage curves on isolated cyclopentene molecules are reproducible and possess negligible hysteresis for a given tip-molecule distance. On the other hand, subsequent measurements with variable tip position show that the negative differential resistance voltage increases with increasing tipmolecule distance. By using a one-dimensional capacitive equivalent circuit and a resonant tunneling model, this behavior can be quantitatively explained, thus providing insight into the electrostatic potential distribution across a semiconductor-moleculevacuum-metal tunnel junction. This model also provides a quantitative estimate for the alignment of the highest occupied molecular orbital of cyclopentene with respect to the Fermi level of the silicon substrate, thus suggesting that this experimental approach can be used for performing chemical spectroscopy at the single-molecule level on semiconductor surfaces. Overall, these results serve as the basis for a series of design rules that can be applied to silicon-based molecular electronic devices.cyclopentene ͉ resonant tunneling ͉ molecular electronics ͉ capacitance ͉ spectroscopy S ince the seminal paper of Aviram and Ratner (1), the field of molecular electronics has undergone rapid growth. Many research efforts are probing the unique charge-transport properties of individual molecules with hopes of revolutionizing electronics and computation. A common experimental approach in this field is to vary the structure of the organic molecule that is placed between two metal electrodes (2-14). However, recent reports suggest that the contacts themselves play a pivotal role in the observed charge-transport behavior of several of these devices (15). This development suggests that, in addition to different molecular systems, alternative contact materials may lead to unique electronic functionality. Because of its compatibility with organic chemistry, its semiconductor band structure, and its ubiquity in commercially available microelectronics, silicon is a promising alternative substrate for molecular electronics.Concurrent with the recent developments in molecular electronics, the ultra-high vacuum (UHV) scanning tunneling microscope (STM) has advanced well beyond its original purpose of probing the structure and properties of materials at atomic length scales (16). Atom manipulation (17-21), nanolithography (22-25), chemical modification (2...

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“…To investigate the effect of electrostatic field ðẼ e Þ in the molecule-electrode interface, we compare the effects of electric fields to the energy gain when the charge redistribution occurs, and the interaction between the charge distribution and the electrostatic field. We regard the electrode-molecule-electrode system as a quasi-parallel-plate capacitor, which has been used in the past [22][23][24][25]. Then the total energy of the system can be written as:…”

Section: Model Theoretical Considerations and Experimental Setupmentioning

confidence: 99%

Electrostatic field effect on molecular structures at metal surfaces

Guo

Zhang

et al. 2009

Surface Science

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Capacitance of a molecular overlayer on the silicon surface measured by scanning tunneling microscopy

Cited by 32 publications

References 16 publications

Kinetic and Thermodynamic Control by Chemical Bond Rearrangement on a Si(001) Surface

Kinetic and Thermodynamic Control by Chemical Bond Rearrangement on a Si(001) Surface

Probing charge transport at the single-molecule level on silicon by using cryogenic ultra-high vacuum scanning tunneling microscopy

Electrostatic field effect on molecular structures at metal surfaces

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