Preparation of self-ordered molecular layers by pulse injection

Grill, Leonhard; Stass, Ingeborg; Rieder, Karl–Heinz; Moresco, Francesca

doi:10.1016/j.susc.2006.03.040

Cited by 24 publications

(38 citation statements)

References 19 publications

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“…2 was annealed under a hydrogen flame for 10 min; the Au substrates used in Figs. 26,28 Grill et al used temperature programed desorption to show that with diethyl ether as solvent, molecules remain on a Cu͑111͒ surface at room temperature. The clean Au͑111͒ was transferred to a sample preparation chamber with a pulsed valve ͑Parker Instrumentation 9-Series, 0.5 mm nozzle diameter, IOTA One driver͒ installed.…”

Section: Methodsmentioning

confidence: 99%

“…28 Disorganized STM images were observed for the sample at 8 K. By annealing the sample at 493 K for ϳ5 min, images of Cu-TBPP monolayer showed clearly discernible molecular-scale structure, and no solvent molecules were observed on the surface. 28 Disorganized STM images were observed for the sample at 8 K. By annealing the sample at 493 K for ϳ5 min, images of Cu-TBPP monolayer showed clearly discernible molecular-scale structure, and no solvent molecules were observed on the surface.…”

Section: Introductionmentioning

confidence: 96%

“…26 In our laboratory, we have used pulsed deposition to prepare samples of Ru2 on Au͑111͒ for imaging with STM. 26,28 Terada et al report that thermal annealing after pulse injection results in substantial improvement in STM image quality, and attribute this to the removal of solvent molecules. Several studies have reported that immediately after pulse deposition, STM images are noisy and of lower quality, and it is speculated that this is caused by a significant number of solvent molecules remaining on the surface.…”

Section: Introductionmentioning

confidence: 99%

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Scanning tunneling microscopy studies of pulse deposition of dinuclear organometallic molecules on Au(111)

Guo

Kandel

2008

The Journal of Chemical Physics

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Ultrahigh-vacuum scanning tunneling microscopy (STM) was used to study trans-[Cl(dppe)2Ru(C Triple Bond C)6Ru(dppe)2Cl] [abbreviated as Ru2, diphenylphosphinoethane (dppe)] on Au(111). This large organometallic molecule was pulse deposited onto the Au(111) surface under ultrahigh-vacuum (UHV) conditions. UHV STM studies on the prepared sample were carried out at room temperature and 77 K in order to probe molecular adsorption and to characterize the surface produced by the pulse deposition process. Isolated Ru2 molecules were successfully imaged by STM at room temperature; however, STM images were degraded by mobile toluene solvent molecules that remain on the surface after the deposition. Cooling the sample to 77 K allows the solvent molecules to be observed directly using STM, and under these conditions, toluene forms organized striped domains with regular domain boundaries and a lattice characterized by 5.3 and 2.7 A intermolecular distances. When methylene chloride is used as the solvent, it forms analogous domains on the surface at 77 K. Mild annealing under vacuum causes most toluene molecules to desorb from the surface; however, this annealing process may lead to thermal degradation of Ru2 molecules. Although pulse deposition is an effective way to deposit molecules on surfaces, the presence of solvent on the surface after pulse deposition is unavoidable without thermal annealing, and this annealing may cause undesired chemical changes in the adsorbates under study. Preparation of samples using pulse deposition must take into account the characteristics of sample molecules, solvent, and surfaces.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Scanning tunneling microscopy studies of pulse deposition of dinuclear organometallic molecules on Au(111)

Guo

Kandel

2008

The Journal of Chemical Physics

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“…42 Methanol was directly injected to the sample surface by using a pulse valve (Parker Pulse Valve series 9) mounted on the UHV chamber. 43,44 Opening and closing cycles of the pulse valve filled with methanol (purity 99.98 %, HPLC grade) were driven by a computer-controlled power supply for a precision control, and the subsequent burst and decay of the chamber pressure following the injection was continuously monitored for the numerical integration and conversion to an equivalent gaseous methanol dose. The placement of the substrate surface from the pulse valve was varied from 50 to 150 mm.…”

Section: Experimental Methodsmentioning

confidence: 99%

Scanning tunneling co-ramp spectroscopy for reactive adsorbates

Choi

Lyo

2011

Phys. Rev. B

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We report the development of a spectroscopy for investigating reactive adsorbates, and its application to the study of chemisorbed methoxy on NiAl(110). Conventional scanning tunneling spectroscopy, a powerful tool to study stable adsorbates, is not applicable to the kinds that decompose or desorb upon the exposure to low-energy tunneling electrons. In order to find the electronic structure of these adsorbates, we developed a scanning spectroscopy that minimizes the exposure to external influences. The coramp spectroscopy (CRS), so named by us, involves synchronized ramping-up of bias V and the spatial position in a constant current mode, and recording the tip-sample separation s(V ) at the same time. Numerical simulations of s(V ) show that the information on the resonance can be extracted from the derivative of s(V ). This technique was applied to the investigation of chemisorbed methoxy deposited by the injection of liquid methanol into NiAl(110) surface. It is shown that slow high-bias scans decompose methoxy through C-O bond scission or C-H bond dehydrogenation. Despite such reactivity of methoxy, CRS was successfully applied to reveal that methoxy has a resonance at 3.4 V. Simulations show that the resonance is well separated from the field emission resonances, and attributed to a nonbonding 2e orbital of chemisorbed methoxy. Our technique should be useful in the study of a wide range of molecular adsorbates, particularly, in the study of their unoccupied states where few techniques are available.

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“…In the investigation of vacuum deposition of metal-containing organic compounds [87][88][89] it was observed that the incorporation of coordinated metal atoms has a stabilizing effect. [90][91][92] The scanning tunneling microscopy (STM) results indicate that the stability of a large organic compound sublimated onto a Au (111) surface under ultrahigh vacuum conditions may be considerably enhanced by coordinating it to gold atoms prior to deposition.…”

Section: Calixarene Complexes With Gold Ionsmentioning

confidence: 99%