Hydrolysis improves packing density of bromine-terminated alkyl-chain, silicon - carbon monolayers linked to silicon

Journal of Physical Chemistry C

Volumn 113, Issue 15, 2009, Pages 6174-6181

  Cohen, Yaron S ^a   Vilan, Ayelet ^a   Ron, Izhar ^a   Cahen, David ^a  

^a WEIZMANN INSTITUTE OF SCIENCE   (Israel)

Author keywords

[No Author keywords available]

Indexed keywords

ALKYL CHAINS; ATOMIC FORCES; CHARGE TRANSPORTS; CURRENT VOLTAGES; DIFFERENTIAL CAPACITANCES; FREE SI; IDEALITY FACTORS; INSULATING LAYERS; INTERMOLECULAR H BONDINGS; MOLECULAR COMPONENTS; PACKING DENSITIES; SCHOTTKY BARRIER HEIGHT MODELS; SCHOTTKY BARRIER HEIGHTS; SELF- ASSEMBLIES; STRUCTURAL CHANGES;

ALKYLATION; ATOMIC SPECTROSCOPY; BROMINE; CAPACITANCE MEASUREMENT; ELECTRON ENERGY LEVELS; ELECTRONIC PROPERTIES; HYDROLYSIS; INFRARED SPECTROSCOPY; SCHOTTKY BARRIER DIODES; SEMICONDUCTING SILICON COMPOUNDS; SEMICONDUCTOR METAL BOUNDARIES; SPECTROSCOPIC ANALYSIS;

MONOLAYERS;

EID: 65249105539     PISSN: 19327447     EISSN: 19327455     Source Type: Journal    
DOI: 10.1021/jp9006125     Document Type: Article

References (49)

1. Alivisatos, A. P.; Barbara, P. F.; Castleman, A. W.; Chang, J.; Dixon, D. A.; Klein, M. L.; McLendon, G. L.; Miller, J. S.; Ratner, M. A.; Rossky, P. J.; Stupp, S. I.; Thompson, M. E. Adv. Mater. 1998, 10, 1297.
2. Ashkenasy, G.; Cahen, D.; Cohen, R.: Shanzer, A.; Vilan, A. Acc. Chem. Res. 2002, 35, 121.
3. Tour. J. M. Acc. Chem. Res. 2000, 33, 791.
4. Scott, A.; Janes, D. B.; Risko, C.; Ratner, M. A. Appl. Phys. Lett. 2007, 91.
5. Aswal, D. K.; Lenfant, S.; Guerin. D.; Yakhmi, J. V.; Vuillaume, D. Anal. Chim. Acta 2006, 568, 84.
6. Langner. A.; Panarello. A.; Rivillon, S.; Vassylyev, O.; Khinast, J. G.; Chabal, Y. J. J. Am. Chem. Soc. 2005, 127, 12798.
7. Eves, B. J.; Fan, C. Y.; Lopinski, G. P. Small 2006, 2, 1379.
8. Linford, M. R.; Chidsey, C. E. D. J. Am. Chem. Soc. 1993, 115, 12631.
9. Linford, M. R.; Fenter. P.; Eisenberger, P. M.; Chidsey, C. E. D. J. Am. Chem. Soc. 1995, 117, 3145.
10. Seitz, O.; Booking, T.; Salomon, A.; Gooding, J. J.; Cahen. D. Langmuir 2006, 22, 6915.
11. Scheres, L.; Arafat, A.; Zuilhof, H. Langmuir 2007, 23, 8343.
12. Green. M. A.; King. F. D.; Shewchun. J. Solid-State Electron. 1974, 17, 551.
13. Salomon, A.; Boecking, T.; Chan, C. K.; Amy, F.; Girshevitz, O.; Cahen, D.; Kahn, A. Phys. Rev. Lett. 2005, 95.
14. Maoz. R.; Frydman, E.; Cohen, S. R.; Sagiv. J. Adv. Mater. 2000, 12, 725.
15. Asanuma, FL; Bishop. E. M.; Yu. H. Z. Electrochim. Acta 2007, 52, 2913.
16. While the Pauling-normalized group electronegativity of OH has been given as 3.4, compared to 3.5 for O and 2.8 for Br, in this case there are actual relevant experimental data, e.g., the dipole moment of bromoethane is 2.03 D, while that of ethanol is only 1.69 D.
17. Jin, H.; Kinser, C. R.; Berlin, P. A.; Kramer, D. E.; Libera. J. A.; Hersam, M. C.; Nguyen, S. T.; Bedzyk, M. J. Langmuir 2004, 20, 6252.
18. Huheev, J. E. Inorganic Chemistry, 3rd ed.; Harper & Row: New York, 1983.
19. XPS measurements at low sample-detector angles have shown increase of both Br 3d and O 1s intensities, implying on the appearance of both Br and OH groups on top of the molecules.
20. We relate the amount of oxygen on top of the monolayer before the hydrolysis to the high reactivity of the Br group as a good leaving group for nucleophylic substitution reactions.
21. Although the appearance of native oxide on Si - H leads to a similar shift of the XPS Si 2p peak, in our case the amount of oxide changes only slightly after hydrolysis and, yet, the Si 2p peak shift is clear. Compare to ref 22.
22. Webb, L. J.; Lewis, N. S. J. Phys. Chem. B 2003, 107, 5404.
23. Faucheux, N.; Schweiss. R.; Lutzow, K.; Werner. C.; Groth, T. Biomaterials 2004, 25, 2721.
24. The presence of silicon oxide (as indicated in the XPS spectrum. Supporting Information, Figure SI-1) may contribute to the high thickness of the monolaver, as well.
25. Edwards, N. V. V. J.; Xie, Q.; Zollner, S.; Werho, D.; Adhihetty, I.; Liu. R.; Tiwald, T. E.; Russell, C.; Vires, J.; Junker, K. H. Mater. Res. Soc. Symp. Proc. 2002, 697, 101.
26. Daimay, L.; Norman, B. C.; William, G. F.; Jeanette, G. G. The Handbook of Infrared and Raman Characteristic Frequencies of Organic Molecules; Academic Press, Inc.: San Diego, CA, 1991.
27. Porter. M. D.; Bright, T. B.; Allara, D. L.; Chidsey, C. E. D. J. Am. Chem. Soc. 1987, 109, 3559.
28. Ulman, A. An Introduction to Ultrathin Organic Films: From Langmuir-Blodgett to Self-Assembly; Academic Press: Boston, 1991.
29. Streitwieser, A.; Heathcock, C. H.; Kosower, E. M. Introduction to Organic Chemistry, 4th ed.; Macmillan Publishing Company: New York, 1992.
30. The silicon oxide is 6 (±1) % of the total coverage of the surface, as also agreed by XPS measurements.
31. The penetration of water and oxygen through the hydrophobic alkyl chain monolayer is less preferred than through the hydrophilic oxidized islands. Consequently, the oxide preferably grows in a lateral manner onto the silicon at the perimeter of the islands and around the islands, rather than in new locations below the bulk of the monolayer. In this way, the molecules in the periphery of the islands become less stable and can be disconnected under the alkaline conditions of the hydrolysis. The claim that molecules are less stable on oxidized silicon is easily demonstrated when immersing the silicon piece, covered with molecules, in HF solution for few minutes.
32. Rampi, M. A.: Whitesides, G. M. Chem. Phys. 2002, 281, 373.
33. Salomon, A.: Bocking, T.; Gooding, J.; Cahen, D. Nano Lett. 2006, 6, 2873.
34. Sze, S. M. Physics of Semiconductor Devices, 2nd ed.; Wiley: New York, 1981.
35. Faber, E. J.; de Smet, L.; Olthuis, W.; Zuilof, H.; Sudholter, E. J. R.; Bergveld, P.; van den Berg, A. ChemPhysChem 2005, 6, 2153.
36. Liu. Y. J.; Yu, H. Z. ChemPhysChem 2003, 4, 335.
37. Tung, R. T. Phys. Rev. B 1992, 45, 13509.
38. Tung, R. T. Mat. Sci. Eng. R 2001, 35, 1.
39. We define as positive a dipole whose positive pole is the one closest to the semiconductor surface.
40. Note that n-type H-Si(111)/Hg contacts exhibited a nearly ohmic response at room temperature, with a very low SB. See ref 41.
41. Maldonado, S.; Plass, K. E.; Knapp. D.; Lewis, N. S. J. Phys. Chem. C. 2007, 111, 17690.
42. After 40 min of hydrolysis, though, the trend is turned over: the currents in reverse bias and in low forward biases increase in comparison to the 20 min hydrolyzed monolayers, which is more typical for charge transport through silicon oxide (see the Supporting Information, Figure SI-3). We assume that at this time scale of hydrolysis, the oxide in the layer becomes dominant in the charge transport.
43. 12 (70 vs 100 mV, respectively). This means that the contribution of oxide to the band bending is negligible and, surely, does not increase the band bending in our case.
44. Cohen. R.; Zenou, N.; Cahen. D.; Yitzchaik, S. Chem. Phys. Lett. 1997, 279, 270.
45. Peor, N.; Sfez, R.; Yitzchaik, S. J. Am. Chem. Soc. 2008, 130, 4158.
46. Cohen. R.; Kronik. L.; Shanzer, A.; Cahen, D.; Liu. A.; Rosenwaks. Y.; Lorenz, J. K.; Ellis, A. B. J. Am. Chem. Soc. 1999, 121, 10545.
47. Thieblemont, F.; Seitz, O.; Vilan. A.; Cohen, H.; Salomon. E.; Kahn, A.; Cahen, D. Adv. Mater. 2008, 20, 3931.
48. Werner, J. H; Guttler, H. H. J. Appl. Phys. 1991, 69, 1522.
49. Tulevski, G. S.; Miao, Q.; Fukuto, M.; Abram, R.; Ocko, B.; Pindak, R.; Steigerwald, M. L.; Kagan, C. R.; Nuckolls, C. J. Am. Chem. Soc. 2004, 126, 15048.