DemoldingENGR 1182.03Pre Lab

Micro/Nanotechnology Tools

One of the challenges of nanotechnology is the limitation of tools available to allow us to “see” into this microscopic world.

Wavelengths vs. Features SizeThe wavelength of a sinusoidal wave is the spatial period of the wave— the distance over which the wave's shape repeats. The smaller the wavelength of the wave the higher the energy of the wave.

Nanotechnology

100 10 10-2 10-4 10-6 10-8 10-10 10-12

Wavelength in meters

MicroscopesAn optical microscope that uses

visible light through lenses can magnify up to 1,500 times! 

 A microscope that uses a beam of electrons instead of light can “magnify” millions of times!

Why the difference? 

ResolutionThe resolution of an image is limited by the

effects of diffraction (Bending of Light).

A good rule of thumb: an imaging system is able to resolve features to approximately half the wavelength of “wave” used

Therefore, the smaller the wavelength the higher the resolution of the microscope

Microscopy using non-lightwavelengths

To obtain higher resolution than optical microscopes, imaging devices using other types of waves have been developed such as electron beam.

Scanning Electron Microscope

An electron beam isfocused and scannedacross a specimen and then scattered electrons are detected. Those scatteredelectrons carry the image information .

Resolution is ~ 5 nm

Focusing

Scanning

Scattered electrons

Cecropia Moth

A close-up of the Cecropia Moth scale using a Scanning Electron Microscope –

Note scale of 1 micron

Scanning Probe MicroscopesThe family of scanning probe

microscopes uses no lenses, but rather a probe that “interacts” with the sample surface.

Some examples are:Scanning Tunneling Microscope (STM)Atomic Force Microscopy (AFM)

Learning Objectives of LabExpose students to a lab-on-a-chip

fabrication technique of demolding PDMS lid from the petridish.