Functional Measurements - Electrical and Optical
Atomic Force Microscopy (AFM)
AFMs are able to operate in a number of modes to allow the user to assess a wide range of electrical properties on a sample. The Asylum Research MFP-3D and the Veeco Multimode are both capable of conductive AFM(C-AFM). The MFP-3D is capable of measuring changes in work function across a surface in scanning Kelvin probe microscopy (SKPM), measure electrostatic forces (EFM) and measure local electrical and mechanical properties of a surface simultaneously using force volume bias spectroscopy (FVBS). The Multimode able to image using scanning tunnelling microscopy (STM).
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Asylum Research MFP-3D |
Veeco Multimode |
Scanning Electron Microscopy (SEM)
The Jeol 6100 SEM has two peripheral systems that allow measurements of electrical and optical properties, particulary for semiconductor materials.
Science City Gatan MonoCL3 cathodoluminescence
(CL) system
- Wavelength range is approx. 300-1000nm (limited by the photomultiplier detector).
- Images can be formed in panchromatic or monochromatic modes
- Luminescence spectra can be collected
- Stage cooling down to liquid nitrogen temperature
Electron beam induced current (EBIC) amplifier
- Measures the current induced in a device caused by electron-hole pairs generated by the electron beam and separated across a depletion region.
- The signal comes from the depletion region, which can be changed by the application of a voltage across the device. Parts of the sample where electrons and holes recombine before they can be collected - such as dislocations - produce dark regions.
- The device must be on an insulating mount and connected to the amplifier with robust wires (the device has to be connected before the SEM door is closed!)
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EBIC image showing misfit dislocations as dark lines in an epitaxial semiconductor layer. Image width is 85 micrometres. |