Chemisorption and Decomposition of Thiophene and Furan on the Si(100)-2 × 1 Surface:  A Quantum Chemical Study

Abstract

The chemisorption and decomposition of thiophene (C 4 H 4 S) and furan (C 4 H 4 O) on the reconstructed Si(100)-2 × 1 surface has been investigated by means of the hybrid density functional (B3LYP) method in combination with a cluster model approach. Two chemisorption mechanisms, i.e., [4 + 2] and [2 + 2] cycloadditions of C 4 H 4 X (X ) S,O) onto a surface dimer site, have been considered comparatively. The calculations revealed that the former process is barrierless and favorable over the latter, which requires a small activation energy (2.6 kcal/mol for thiophene and 1.2 kcal/mol for furan). The di-σ bonded surface species formed by [4 + 2] cycloaddition-type chemisorption can either undergo further [2 + 2] cycloaddition with a neighboring SidSi dimer site, giving rise to a tetra-σ bonded surface species, or undergo deoxygenation (desulfurization) by transferring the heteroatom to a neighboring SidSi dimer site, leading to a six-member ring metallocyclic C 4 H 4 Si 2 surface species. The latter process was found to be slightly more favorable than the former, especially in the case of thiophene.

Theoretical investigations on CH2CH–CH2OH on the Si(100)-2×1 and Ge(100)-2×1 surfaces

“…Although B3LYP has a tendency to underestimate barriers with a typical error of about 4.0 kcal/mol [41], B3LYP has been used extensively to calculate unsaturated hydrocarbon compounds and alcohols on the Si(1 0 0)-2 · 1 surface with the cluster approximation. These results are generally in good agreement with the experiments [25,30,[34][35][36]42,43]. Therefore, it is expected that B3LYP is reasonable for the present system.…”

“…A Si 15 H 16 and Ge 15 H 16 two-dimer cluster model is used to model the Si(1 0 0)-2 · 1 surface. This model includes the four silicon atoms representing the surface atoms and the eleven silicon atoms composing subsurface bulk atoms as described in previous theoretical investigations [34][35][36]. The dangling bonds of the subsurface atoms are terminated by hydrogen atoms.…”

Atomic and electronic properties of furan on the Si(001)-(2×2) surface

“…This rapidly growing field has been considered in a large number of experimental and theoretical investigation so as to elucidate the structural and electronic properties of such systems [4][5][6][7][8]. Among the heterocyclic hydrocarbons, the interaction of the thiophene (C 4 H 4 S) [9][10][11] and furan (C 4 H 4 O) [12][13][14] with the Si(1 0 0) surface has also attracted with a great attention because this organic semiconductor structures is the backbone of the highly ordered thin-film conducting polymers.…”

Reverse bias capacitance–voltage characteristics of Al/polyaniline/p-Si/Al structure as a function of temperature

“…Rectification behavior of PANI based Schottky barrier was used as a sensor for the detection of the methane gas [11]. So far many attempts have been made to realize a modification of the barrier height or the continuous control of the barrier height using an organic semiconductor layer [12][13][14][15][16][17] or an insulating layer and a chemical passivation procedure [18][19][20][21][22][23] at certain metal/inorganic semiconductor interfaces, or to determine characteristic parameters of organic film [12][13][14][15][16][17]. In general, the organic materials are characterized by wide energy gaps and low electrical conductivities, and as a consequence, charge injection from the electrodes is a common phenomenon.…”