Study on Electrical Characteristic of Self-assembled Nitro Molecule Onto Au(111) Substrate by Using STM/STS

STM/STS에 의한 Au(111) 표면에 자기조립된 니트로분자의 전기적 특성 측정

  • Published : 2006.01.01

Abstract

The characteristic of negative differential resistance(NDR) is decreased current when the applied voltage is increased. The NDR is potentially very useful in molecular electronics device schemes. Here, we investigated the NDR characteristic of self-assembled 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate, which has been well known as a conducting molecule. Self-assembly monolayers(SAMs) were prepared on Au(111), which had been thermally deposited onto $pre-treatment(H_2SO_4:H_2O_2=3:1)$ Si. The Au substrate was exposed to a 1 mM/1 solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing the sample, it was exposed to a 0.1 ${\mu}M/l$ solution of 4.4'-di(ethynylphenyl)-2'-nitro-1-(thioacetyl)benzene in dimethylformamide(DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. After the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_2Cl_2,$ and finally blown dry with N_2. Under these conditions, we measured electrical properties of self-assembly monolayers(SAMs) using ultra high vacuum scanning tunneling microscopy(UHV-STM). The applied voltages were from -2 V to +2 V with 298 K temperature. The vacuum condition was $6{\time}10^{-8}$ Torr. As a result, we found the NDR voltage of the 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate were $-1.61{\pm}0.26$ V(negative region) and $1.84{\pm}0.33$ V(positive region). respectively.

Keywords

References

  1. Arieh Aviram and Mark A. Ratner, 'Molecular rectifiers', Chem. Phys, Lett., Vol. 29, pp. 277-283, 1974 https://doi.org/10.1016/0009-2614(74)85031-1
  2. Tali Dadosh, Yoav Gordin, Romman Krahne, IlYa Khivrich, Dianna Mahalu, Veronica Frydman, Joseph sperling, Amir Yacoby & Israel Bar-Joseph, 'Measurement of the conductance of single conjugated molecules', Nature, Vol. 436, pp. 677-680, 2005 https://doi.org/10.1038/nature03898
  3. Young-seok Shon and T. Randall Lee, 'A Steady-State Kinetic Model Can Be Used to Describe the Growth of Self-Assembled Monolayers(SAMs) on Gold', J. Phys. Chem. B., Vol. 104, pp. 8182-8191, 2000 https://doi.org/10.1021/jp000650p
  4. Hannoch Ron, Sophie Matlis, and Israel Rubinstein, 'Self-Assembled Monolayers on Oxidized Metals. 2. Gold Surface Oxidative Pretreatment, Monolayer Properties, and Depression Formation', Langmuir, Vol. 14, pp. 1116-1121, 1998 https://doi.org/10.1021/la970785v
  5. A. Kirakosian, M. J. Comstock, jongweon Cho, and M. F. Crommie, 'Molecular commensurability with a surface reconstruction: STM study of azobenzene on Au(111)', Phys. Rev. B., Vol. 71, pp. 113409-113409-4, 2005 https://doi.org/10.1103/PhysRevB.71.113409
  6. J. Chen, W. Wang, and M. A. Reed, A. M. Rawlett, D. W. Price, and J. M. Tour, 'Room-temperature negative differential resistance in nanoscale molecular junctions', Appl. Phys. Lett., Vol. 77, pp. 1224-1226, 2000 https://doi.org/10.1063/1.1289650
  7. J. Chen, M. A. Reed, A. M. Rawlett and J. M. Tour, 'Large On-Off Ratios and Negative Differential Resistance in a Molecular Electronic Device', Science, Vol. 286, pp. 1550-1552, 1999 https://doi.org/10.1126/science.286.5444.1550
  8. Lintao Cai, Yuxing Yao, Jiping Yang, David W. Price, Jr., and James M. Tour, 'Chemical and Potential-Assisted Assembly of Thiolacetyl-Terminat ed Oligo(phenylene ethynylene)s on Gold Surfaces', Chem. Mater., Vol. 14, pp. 2905-2909, 2002 https://doi.org/10.1021/cm011509b
  9. Nam-Suk Lee, Hoon-Kyu Shin and Young-Sao Kwon, 'A Study on the Negative Differential Resistance in Dipyridinium Self-Assembled Monolayers Using STM', KIEE International Transactions on Electrophysics and Applications, Vol. 5-C, pp. 111-114, 2005
  10. Seung-Un Kim, Hoon-Kyu Shin and Young-Sao Kwon 'A Study on the Current-Voltage Characteristics of Self-Assembled Organic Molecules by using STM', KIEE International Transactions on Electrophysics and Applications, Vol. 5-C, pp. 115-118, 2005
  11. Chr. Wittneven and R. Dombrowski, S. H. Pan, R. Wiesendanger, 'A low-temperature ultrahigh-vacuum scanning tunneling microscope with rotatable magnetic field', Rev. Sci. In strum., Vol. 68, pp. 3806-3810, 1997 https://doi.org/10.1063/1.1148031