|
|
|
|
Field Emission Scanning Microscopy/Energy
Dispersive X-ray Analysis (FESEM/EDX)
Scanning electron microscopy (SEM) is one of the most versatile and well
known analytical techniques. Compared to conventional optical microscope,
an electron microscope offers advantages including high magnification,
large depth of focus, great resolution and ease of sample preparation
and observation. Electrons generated from an electron gun enter
a surface of a sample and generate many low energy secondary electrons.
The intensity of these secondary electrons is governed by the surface
topography of the sample. An image of the sample surface is therefore
constructed by measuring secondary electron intensity as a function
of the position of the scanning primary electron beam.
In
addition to secondary electrons imaging, backscattered electrons
imaging and Energy Dispersive X-ray (EDX) Analysis are also useful
tools widely used for chemical analysis. The intensity of backscattered
electrons generated by electron bombardment can be correlated to
the atomic number of the element within the sampling volume. Hence,
qualitative elemental information can be revealed. The characteristic
X-rays emitted from the sample serve as fingerprints and give elemental
information of the samples including semi-quantitative analysis, quantitative
analysis, line profiling and spatial distribution of elements. SEM with
X-ray analysis is efficient, inexpensive, and non-destructive to surface
analysis. It has wide ranges of applications both in industry and
research.
In the SML, a state-of-the-art high resolution LEO 1530
field emission scanning electron microscope with EDX system from
OXFORD is available. It is a high performance instrument designed
for analytical applications featuring the GEMINI column technology.
It is controlled by a 32 bit computer system using Microsoft Windows
NT as operating system.
Figure 1 Schematic diagram
of the LEO 1530 Field Emission SEM.
Figure 2 LEO 1530 Field Emission SEM.
LEO 1530 Specifications
- Resolution: 1.0nm at 20KV WD=2mm
- 2.1nm at 1KV WD=1mm
- Accelerating Voltage: 0.1KV to 30KV continuously
variable in 10 volt steps.
- Magnification: 20X to 900KX
- Probe current: 4pA to 10nA
- Electron gun: thermal field emission type
- In-lens annular, Secondary Electron (SED), Backscattered Electron (BSD)
- EDX: working distance 8.5mm
- Image Processing: pixel averaging, frame integration, continuous
averaging
- Image Resolution: 512 x 384 to 3072 x 2304 pixel
Some SEM Image measured by LEO1530 Scanning Electron Microscope:
Some SEM/EDX result
measured by LEO1530 Scanning Electron Microscopy:
SEM and EDX Mapping
Measured by LEO1530 Scanning Electron Microscopy:
For further enquiry, please contact Mr. Benson Leung, Tel: (852)
34115876, email scleung@hkbu.edu.hk
|
|
