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NanoTransport Laboratory Temperature Dependent Molecular Conduction measured by the Electrochemical Deposition of Platinum Electrode in Lateral Configuration.

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Presentation on theme: "NanoTransport Laboratory Temperature Dependent Molecular Conduction measured by the Electrochemical Deposition of Platinum Electrode in Lateral Configuration."— Presentation transcript:

1 NanoTransport Laboratory Temperature Dependent Molecular Conduction measured by the Electrochemical Deposition of Platinum Electrode in Lateral Configuration (Applied Physics Letters, 2004 (in press)) B. Kim*, S. J. Ahn*, J. G. Park*, S. H. Lee*, E. E. B. Campbell**, Y. W. Park* * School of Physics, Seoul National University, Korea ** Department of Experimental Physics, Gothenburg University and Chalmers University of Technology, Sweden

2 NanoTransport Laboratory I.Introduction II.Sample preparation (1,4-benzenedimethanethiol (BDMT) ) III. Result and discussion: Temperature dependent molecular conduction (27K { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/12/3452868/slides/slide_2.jpg", "name": "NanoTransport Laboratory I.Introduction II.Sample preparation (1,4-benzenedimethanethiol (BDMT) ) III.", "description": "Result and discussion: Temperature dependent molecular conduction (27K

3 NanoTransport Laboratory Polyacetylene single nanofiber(PANF) SEM image Synthetic Metals 119, 53 (2001) AFM image 0.8 micron Poster 24: Bio Kim et al.

4 NanoTransport Laboratory Scanning tunneling microscope M. Dorogi, et al., Phys. Rev. B, 52, 9071 (1995) S. Datta, et al., Phys. Rev. Lett. 79, 2530 (1997)

5 NanoTransport Laboratory Conducting atomic force microscope X. D. Cui, et al., Science, 294, 571 (2001)D. J. Wold, et al., J. Am. Chem. Soc. 123, 5549 (2001)

6 NanoTransport Laboratory Mechanically controlled break junction M. A. Reed, et al., Science, 278, 252 (1997) J. Reichert, et al., Phys. Rev. Lett. 88, 176804 (2002)

7 NanoTransport Laboratory Electromigration break junction H. Park, et al., Appl. Phys. Lett. 75, 301 (1999) J. Park, et al., Nature 417, 722 (2002)

8 NanoTransport Laboratory Angle evaporation J. O. Lee, et al., Nano Lett. 3, 113 (2003) N. B. Zhitenev, et al., Phys. Rev. Lett. 88, 226801 (2002)

9 NanoTransport Laboratory Others J. G. Kushmerick, et al., Nano Lett. 3, 897 (2003) J. K. N. Mbindyo, et al., J. Am. Chem. Soc. 124, 4020 (2002)

10 NanoTransport Laboratory Molecular conduction measured by the electromigration technique 1. Electromigration H. Park, et al., Nature 407, 57 (2000) 200 nm 2 ㎛ 2. Electrode design 20 nm height of Au electrode without adhesion layer

11 NanoTransport Laboratory 3. Breaking of Au line 4. AFM and SEM image of nano gap

12 NanoTransport Laboratory Y. V. Kervennic, et al., Appl. Phys. Lett. 80, 321 (2002) (2) reducing the separation of electrodes using electrochemical deposition of Pt (1) SAM on top of Au electrode/nanoparticles Our method: Molecular conduction measured by the electrochemical deposition David L. Klein et al., APL 68, 2574 (1996)

13 NanoTransport Laboratory A 3. deposit Pt electrochemically Pt 4. measure IV characteristics A this 1. grow self-assembled monolayers (SAMs) SAMs pin hole 2. compose circuit and drop solution A aqueous solution of 0.1 M of K 2 PtCl 4 and 0.5 M of H 2 SO 4 Our method : (1) + (2) combination of electrochemical deposition and SAM Schematic diagram

14 NanoTransport Laboratory Electrochemical deposition process of Pt R > 10 G  time Optical microscope image confirms the deposition of Pt on one side. After drying electrolyte In situ In the electrolyte

15 NanoTransport Laboratory 100 nm Pt before deposition after deposition AFM & FESEM image height ~ 700 nm side view (conjecture) Pt SiO 2

16 NanoTransport Laboratory Measurement results & discussion open R > 10 G  short R ~ 5 k  sample non-Ohmic At Room Temperature

17 NanoTransport Laboratory Temperature dependent I-V characteristics (160K { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/12/3452868/slides/slide_17.jpg", "name": "NanoTransport Laboratory Temperature dependent I-V characteristics (160K

18 NanoTransport Laboratory Temperature dependent I-V characteristics (29K { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/12/3452868/slides/slide_18.jpg", "name": "NanoTransport Laboratory Temperature dependent I-V characteristics (29K

19 NanoTransport Laboratory Tunneling at low temperature (T<40K) Fowler-Nordheim tunneling: log(I /V 2 ) ∝ -1/V sample 1

20 NanoTransport Laboratory Temperature dependent I-V characteristics (100K { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/12/3452868/slides/slide_20.jpg", "name": "NanoTransport Laboratory Temperature dependent I-V characteristics (100K

21 NanoTransport Laboratory Temperature dependent I-V characteristics (27K 0.85 V at 50 K < T < 60 K. sample 2

22 NanoTransport Laboratory I-V characteristics – sample 2 No switching or NDR effect upon voltage sweep at T=27K After sweeping the voltage, the current is increased ~5 times At T=27K

23 NanoTransport Laboratory I-V characteristics (30K { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/12/3452868/slides/slide_23.jpg", "name": "NanoTransport Laboratory I-V characteristics (30K

24 NanoTransport Laboratory Tunneling at low temperature (T<40K) Fowler-Nordheim Tunneling: log(I /V 2 ) ∝ -1/V sample 2

25 NanoTransport Laboratory Model for the asymmetric I-V characteristics HOMO LUMO Chemisorbed Pt Physisorbed Pt positive bias to ‘physisorbed Pt’ negative bias to ‘physisorbed Pt’ eV Contact between base Pt and SAM is much better (chemisorbed) than contact between electrochemically grown Pt and SAM (physisorbed).

26 NanoTransport Laboratory Summary · Temperature dependent molecular conduction was measured by the electrochemical deposition of platinum electrode to the self-assembled monolayer of 1,4-benzenedimethanethiol (BDMT) in lateral configuration. · I-V characteristics are non-Ohmic and asymmetric in all measured temperature range. (27 K < T < 300 K) · For T>40K, the I-V characteristics are semiconductor-like. · For T  40K, the I-V characteristics are temperature independent following the Fowler-Nordheim type Tunneling conduction. ( log (I /V 2 ) ∝ -1/V )

27 NanoTransport Laboratory Acknowledgement: This work was supported by the National Research Laboratory (NRL) program of the Ministry of Science and Technology (MOST), Korea. Work done in Sweden was supported by the Sweden Strategic Research Fund (CARAMEL consortium) and STINT. Partial support for Yung Woo Park was provided by the Royal Swedish Academy of Science.


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