Activities during UK-Japan Young Scientist Workshop

1. Activities during UK-Japan Young Scientist Workshop Dr Riz Khan Room 31DJ02, x6062, e-mail: r.khan@surrey.ac.uk Advanced Technology Institute University of Surrey

2. Learning Outcomes • What do we want you to learn? • Which techniques will you be using? • What will you take away?

3. Literature searching • We have set up a number of computers in the CAD room for you to use • We want you to search for information on the internet related to nanotechnology • Also search for the experiments that you will be doing • Research is the key to scientific success!

4. Computer aided design • We will ask you to design structures to be written on a nano-scale • This will be done in the CAD laboratory (04DJ01) • The images should be of different sizes so that you can see what the resolution of the equipment is • How would you do this?? • Good examples are e.g. your names in English and Japanese, scanned-in pictures etc

5. Focussed Ion Beams • Focussed ion beams (FIBs) are used to write structures on the nanoscale • Creates a beam of ions (5-30 keV) that bombard and erode the sample • Milling commonly done in high vacuum • Resolutions approaching 10 nm • What is the resolution of ours?

6. Focussed ion beams • Our machine! • (and out PhD students and scientific staff) • 10 superconducting junctions, University of Cambridge Materials dept

7. Imaging / microscopy techniques

8. Light versus electrons…

9. Scanning electron microscopy • Use a beam of highly energetic electrons to examine objects on a very fine scale: • Topography • Morphology • Composition (if appropriate detector equipped) • Samples normally conductive or coated with thin conductive layer Electron beam (0.1-50 keV) Secondary electrons (low E) Backscattered electrons (high E) Light (cathodoluminescence) X-rays } 1 micron 10 nm {

10. Scanning electron microscopy • Electron beam source - filament (W or LaB6) or field emission • Focused to 1-5 nm spot size, scanned over sample • Incident electrons either: • Scatter back • Knock other electrons out (secondary electrons) • Secondary electrons - greater in number Backscattered electrons - Z sensitive Secondary electrons - Z-insensitive compositional information • Analysis of x-ray emission (energy dispersive x-ray spectroscopy, EDX) gives elemental analysis

11. Scanning electron microscopy • Typical image… Already well used in microelectronics, biology, materials science, etc

12. Atomic Force Microscopy • Tip mounted on flexible cantilever • Atomic (Van der Waals) forces result in deflection of tip • Measured using deflection of a laser beam incident on the cantilever detector laser cantilever tip

13. Atomic Force Microscopy • Contact mode • constant force between tip and surface (constant deflection) • Non-contact mode • Cantilever is oscillated • Oscillation frequency changed by atomic force • Compared to reference frequency • More sensitive Contact mode is simpler to perform • but has poorer resolution / contrast and can damage the film surface

14. Timetable • Monday 2-4:30 • Talks - JA, RK • Tour of facilities - Steve Lyth, Yoji • Introduction of CAD and internet facilities • Tuesday 10-12 • design structures to be FIB'd. • Place - CAD room (Yoji) • Tuesday 2-4:30 • Nanostructures written by FIB (David Cox) - three groups! • Place - FIB / microscopy room • Waiting students perform internet research in CAD room

15. Timetable • Thursday 10-4:30 • AFM and SEM on the structures. (Yann Tison, Steve Lyth) - same groups as before • Place - FIB / microscopy room • We have a number of other secret structures to look at! • Other students perform internet research in CAD room • Friday morning • Preparation for presentation • Place - CAD room • Assistance - Yoji • Friday afternoon - presentations!

16. Any questions?