Vjachslav Ksenofontov PhD senior researcher mikhailovskij@kipt.kharkov.ua

1. Vjachslav Ksenofontov PhDsenior researcher mikhailovskij@kipt.kharkov.ua High-field technology for processing of nano-sized objects National Scientific Centre “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine

2. Developed technology for nano-scaled objects provides for surface modification into atomically smooth state. Applications: - ultra-sharp atraumatic microsurgical instruments; - ultra-fine microprobes for scanning tunneling microscopes; - field emitters with localized emission.

3. The technology is based on the discovered phenomenon of field evaporation of metals in dielectric liquids and gas stimulated field evaporation. • Previous method of field evaporation in high vacuum, faced problem caused by the destruction of objects under mechanical stress generated by super-high electric field.

4. SMOOTHING METAL SURFACE BY LOW-TEMPERATURE FIELD EVAPORATION UHV conditions, T=21 K Atomic smoothing during field evaporation Surface of tungsten nanotip before treatment Destruction at mechanical stress due to high electric field F = 60V/nm, σ = 20 GPa (Theoretical Strength)

5. SURFACE FORMING BY FIELD DESORPTION (Computer modeling) Nanotip [100] orientation Pulse field desorption Evaporation rate 0.01 nm/s Alternative field evaporation of nanotips KIPT Kharkov, together with Oxford University, UK (Prof. G.Smith) and Hahn-Meitner-Institute,Berlin (Dr.N.Wanderka)

6. PHENOMENON OF LOW-TEMPERATURE FIELD EVAPORATION IN DIELECTRIC LIQUIDS High-field forming without mechanical destruction Electron microscopic image of W microtip after high-field treatment in liquid nitrogen a b FIM images W nanotips formed by evaporation in liquid nitrogen at 0.4 kV (a) and 1.2 kV (b). Joint patents with Dr. R. Forbes, University of Surrey School of Electronic, UK Dr. N. Wanderka, Hahn-Meitner-Institute, Berlin, Germany

7. RATES OF FIELD EVAPORATION IN DIELECTRIC LIQUIDS AND ACTIVE GASES Gases hydrogen stimulated evaporation. Nb-Ti at 0.82 (1) and 0.25 (2) Pa Evaporation in UHV (1) and liquid nitrogen (2) of W Blunting of nanotips Sharpening of nanotips Joint patent with Dr. R. Forbes, University of Surrey School of Electronic, UK

8. FIELD EVAPORATION IN ACTIVE GASES Sharpening of nanotips 15 s 10 s 5 s R=2 nm 0 s W – N2 Nanotip [100] orientation

9. HIGH-FIELD FORMING OF STM MICROPROBES AND MICROSURGICAL INSTRUMENTS STM probe before (a) and after (b) high-field sharpening a b Graphite surface image obtained in the STM with an atomically smooth microprobe a b Microknife (a) andSatoknife (b) Segment of market related to medical instrumentation is about 100000 per year

10. CNT-film (random) CNT (regular array) PROBLEM OF FIELD-EMISSION NON-UNIFORMITY CNT bundles (aligned) SEM image of cross-section of film Large-scale field emission J.Chen et al,Ultramicroscopy 95 (2003) 153 Collapsed CNTs W.Yu et al, Nanotechnology 16 (2005) S291 Top-down view

11. Next step proposed - HIGH-FIELD FORMING OF CARBON, SILICON, AND OXIDE NANO-SIZED OBJECTS - SELF-CONSISTENT HIGH-FIELD FORMING OF NANORELIEF Field-ion emission of nanofibre carbon emitter b c a Nanorelief before (a), during (b) and after (c) stimulated field evaporation

12. OUR TEAM Mikhailovskij Igor, Dr. Sci., Prof., Leading researcher Mazilova Tatjana, Dr Sci, Senior researcherKsenofontov Vjacheslav, PhD, Senior researcherVelikodnaya Olga, PhD, Researcher Sadanov Evgenij, PhD, Researcher Thank you for your attention!