Experimental and Theoretical Studies of Trimethylene Sulfide-Derived Nanostructures on p- and n-Type H-Silicon(100)-2 × 1

Abstract

The nanoscale structuring of molecules on silicon surfaces is one approach for combining the tuneable properties of chemical species with the functionality of semiconductor materials. In this study, we report on the growth characteristics of trimethylene sulfide (TMS) on p- and n-type H−Si(100)-2 × 1. The nanostructures formed by TMS on either surface are indistinguishable by scanning tunneling microscopy (STM). However, high-resolution electron energy loss spectroscopy (HREELS) and modeling by density functional theory indicate that the molecular attachment mechanism differs with dopant type. Our results show that TMS adds to a surface silicon dangling bond through the formation of a Si−S bond on p-type silicon and through the formation of a Si−C bond on n-type silicon. In both cases, the added TMS undergoes ring opening following covalent bond formation with the surface. The different ring-opened radicals are able to abstract a hydrogen atom from one of two neighboring silicon dimers. The overall reaction produces TMS-derived nanostructures that grow via a square-wave pattern on the neighboring edges of two dimer rows.

Scanning tunneling microscopy study of one-dimensional o-phthalaldehydechain reactions on the Si(100)-2 × 1:H surface

“…STM images of the type A and type B nanostructures have many similarities to images of other one-dimensional organosilicon nanostructures that possess a single covalent bond per molecule to the surface. [14][15][16][17][18][19][20][21][22][23] For example, type A lies along one side of the dimer row, which is consistent with molecules covalently attached to only one side of the silicon dimer. The growth mechanism for the type A nanostructures can thus be attributed to a chain reaction initiated at an isolated DB site.…”

“…[10][11][12][13] While many variations of these molecules and their interactions with organic and inorganic nanostructures have been investigated, previous studies have focused exclusively on molecules that bind to the silicon surface via one covalent bond. [14][15][16][17][18][19][20][21][22][23] On the other hand, o-phthalaldehyde (OP), which contains two aldehyde end groups, was recently predicted to form one-dimensional nanostructures on the Si(100)-2 Â 1:H surface in which each OP molecule would be attached to the surface via two covalent Si-O bonds. 24 This communication details a molecular resolution UHV STM study of OP on the Si(100)-2 Â 1:H surface.…”

Chemical manipulation of multifunctional hydrocarbons on silicon surfaces

“…However, it is perfect for abstraction of a hydrogen atom from the neighboring row, thus creating a molecular line perpendicular to the direction of propagation of the silicon dimer row [415]. If trimethylene sulfide is used instead of allyl mercaptane on H-terminated Si (111), a structurally similar surface species is obtained, except that in this case Si-S bond is formed on ptype silicon, while Si-C bond is formed on n-type silicon [441], demonstrating a novel doping-dependent handle for controlling silicon surface chemistry. The combination of the chemistries of styrene and allyl mercaptane on a H-terminated Si(100) surface allows for designing specific two-dimensional molecular architectures on this substrate as shown in the STM studies summarized in Fig.…”

Reaction of a hydrogen-terminated Si(100) surface in UHV with ion-pump generated radicals

“…2 Numerous studies of molecular line growth 3 also rely strongly on highquality H-terminated Si surfaces. [5][6][7][8] The process begins with a molecule bonding to an isolated surface dangling bond ͑DB͒, which leaves an unpaired electron on one atom of the molecule. 3 Subsequently, many different organic molecules have been found to form nanostructures via a self-directed process on the H-Si surface in the same way.…”