Activities during UK-Japan Young Scientist Workshop Dr Riz Khan Room 31DJ02, x6062, Advanced Technology Institute University of Surrey

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

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!

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

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?

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

Imaging / microscopy techniques LimitResolution EyeRetina nm Optical microscopeDiffraction of light 300 nm Scanning electron microscope Diffraction of electrons 3 nm Transmission electron microscope Diffraction of electrons 0.1 nm Scanning probe microscope Aperture0.01 nm

Light versus electrons…

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 ( keV) 10 nm { } 1 micron Backscattered electrons (high E) Secondary electrons (low E) X-rays Light (cathodoluminescence)

Scanning electron microscopy Electron beam source - filament (W or LaB 6 ) 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

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

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 laser detector cantilever tip

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

Timetable Monday 2-4:30 Talks - JA, RK Tour of facilities - Steve Lyth, Yoji Introduction of CAD and internet facilities Tuesday 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

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!

Any questions?