Dehydrohalogenation Condensation Reaction of Phenylhydrazine with Cl-Terminated Si(111) Surfaces

Abstract

Formation of stable organic–inorganic contacts with silicon often requires oxygen- and carbon-free interfaces. Some of the general approaches to create such interfaces rely on the formation of a Si–N bond. A reaction of dehydrohalogenation condensation of Cl-terminated Si(111) surface with phenylhydrazine is investigated as a means to introduce a simple function to the surface using a –NH-NH2 moiety as opposed to previously investigated approaches. The use of substituted hydrazine allows for the formation of a stable structure that is less strained compared to the previously investigated primary amines and leads to minimal surface oxidation. The process is confirmed by a combination of infrared studies, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry investigations. Density functional theory is utilized to yield a plausible surface reaction mechanism and provide a set of experimental observables to compare with these data.

Reaction of Hydrazine with Solution- and Vacuum-Prepared Selectively Terminated Si(100) Surfaces: Pathways to the Formation of Direct Si–N Bonds

“…This shift to a lower binding energy is due to the lower electronegativity of nitrogen compared to oxygen, and it can be clearly differentiated on the silicon surface. 22,24,53 It should be noted that on H−Si(100) reacted with hydrazine (Figure 1b), the intensity of the peak that corresponds to partial oxidation at 103.7 eV is much smaller than that on H− Si(100) before the reaction with hydrazine (Figure 1a). This may be the result of shorter exposure time for transferring the H−Si(100) sample for the hydrazine reaction compared to that required to transfer it to the XPS chamber or may indicate oxide removal during hydrazine modification.…”

Monolayer of Hydrazine Facilitates the Direct Covalent Attachment of C60 Fullerene to a Silicon Surface

“…The calibration of ToF-SIMS data was performed using ION-TOF measurement explorer software (version 6.3). The calibration masses were H + , H 2 + , H 3 + , C + , CH + , CH 2 + , CH 3 + , C 2 H 3 + , C 3 H 5 + , C 4 H 7 + , C 5 H 5 + , C 6 H 5 + , and C 7 H 7 + in positive mode and H – , H 2 – , C – , CH – , CH 2 – , CH 3 – , C 2 – , C 2 H – , C 3 – , C 4 – , C 5 – , C 6 – , C 7 – , C 8 – , and C 60 – in negative mode. , …”

“…18 At the same time, the previously attempted approach to produce a chemical functionality on a silicon surface by directly reacting functionalized hydrazine with Cl-terminated silicon resulted in a very low coverage and facile oxidation of the interface. 30 Thus, two-step functionalization, where the first step is silicon modification with hydrazine and the second step is the attachment to this prepared platform, should provide a more reliable path for producing the desired interface. The chemical nature and surface topography of the resulting C 60 -modified Si(111) surfaces are investigated by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic-force microscopy (AFM).…”

“…The choice of hydrazine to form the first layer instead of previously investigated ammonia , and amines , offers high stability and controlled reactivity of the resulting functional group . At the same time, the previously attempted approach to produce a chemical functionality on a silicon surface by directly reacting functionalized hydrazine with Cl-terminated silicon resulted in a very low coverage and facile oxidation of the interface . Thus, two-step functionalization, where the first step is silicon modification with hydrazine and the second step is the attachment to this prepared platform, should provide a more reliable path for producing the desired interface.…”

Orientation and stability of a bi-functional aromatic organic molecular adsorbate on silicon

“…Determining the adsorption structures of organic molecules on the technologically important Si(001) surface is an important fundamental step toward this goal. [5][6][7][8][9][10][11][12][13][14] Recent advances in atomic-scale imaging, photoelectron and X-ray absorption spectroscopy, and theoretical calculations now provide us with the ability to determine the structure of surface adsorbates with atomic-scale precision. Scanning tunnelling microscopy (STM) can provide atomically-resolved images of individual adsorbates, often resolving key features that are critical to the correct identification of the structures.…”