activities during uk-japan young scientist workshop
DESCRIPTION
Activities during UK-Japan Young Scientist Workshop. Dr Riz Khan Room 31DJ02, x6062, e-mail: [email protected] 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?. - PowerPoint PPT PresentationTRANSCRIPT
Activities during UK-Japan Young Scientist Workshop
Dr Riz Khan
Room 31DJ02, x6062, e-mail: [email protected]
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
Limit Resolution
Eye Retina 70 000 nm
Optical microscope Diffraction of light
300 nm
Scanning electron microscope
Diffraction of electrons
3 nm
Transmission electron microscope
Diffraction of electrons
0.1 nm
Scanning probe microscope
Aperture 0.01 nm
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)
10 nm { } 1 micron
Backscattered electrons (high E)
Secondary electrons (low E)
X-raysLight (cathodoluminescence)
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 sensitiveSecondary 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
cantilevertip
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 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
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!