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Click here to view actual size (1152 x 862) Zoom in of Scan Mode image showing evolution of specular and 1st order diffraction streaks during the MBE growth of Cu on Au (111) at 150C. Time (thickness) increases as you go from the top to the bottom of the image. Note the "bowing" of the 1st order diffraction streaks, indicative of the change in lattice spacing during growth. Note also the specular RHEED oscillations. The blue rectangle defines the region plotted in 3D, shown in (2). The red rectangle defines the region for lattice spacing calculation shown in (3). Scan Mode images are a natural, informative way to store diffraction pattern evolution without requiring complete image storage. 3D image of blue rectangle region in (1), showing the evolution of 1st order and specular diffraction streaks during the growth of Cu and Au (111) at 150C. 3D plots are very useful in showing, for example the evolution of a growth, anneal, or adsorption/desorption process. Note that all kSA 400 analysis routines are interactive: as you drag or resize an analysis region, the resulting analysis chart is immediately displayed and continuously updated. Lattice spacing evolution for the growth of Cu on Au (111)at 150C. The red rectangle in (1) defines the region of the Scan Mode image over which to calculate the lattice spacing. During this growth, a large (8.3%) change in in-plane lattice spacing occurs. Scan Mode image showing the evolution of the specular spot during the growth of GaAs on GaAs (100). Time (thickness) increases from the top to the bottom of the image. The specular intensity oscillations are readily visible. The various colored boxes define the analysis regions in windows (5), (6), (7), and (8). GaAs (100) specular intensity oscillations from the Scan Mode image in (4). The peak intensity is plotted here, but average, centroid, and center intensity may also be plotted. The intensity analysis region to analyze is defined by the box overlayed on the Scan Mode image in (4). FFT of the GaAs specular intensity oscillations shown in (5). The peak yields a GaAs growth rate of 0.33 ML/sec. The FFT algorithm employed by the kSA 400 includes a data mirroring option, which can greatly improve the growth rate determination accuracy. The FFT algorithm can be applied to any displayed data set. Coherence length evolution of the GaAs specular beam evolution shown in (4). The full width at half maximum (FWHM) for each line profile in (4) is determined. Through instrument calibration parameters, the FWHM evolution is then converted to the average in-plane coherence length. In the homoepitaxial GaAs growth analyzed here, the coherence length is a measure of the average island size during growth; hence the oscillations in width. Note that an FFT on coherence length data plotted here yields the identical peak frequency as determined from the intensity oscillations in (5). 3D representation of the GaAs specular beam evolution in (5). Note the peak width dependence in addition to the intensity dependence. The kSA 400 User Manual is completely integrated into the kSA 400 software. Every aspect of the kSA 400, from theory of camera operation to lattice spacing calibration, is covered in this manual. The manual is context sensitive with hypertext, so if you have a question on a window, display, acquisition mode, etc. just hit F1 to get help. Alternatively, a detailed table of contents and index is included. All images stored with the kSA 400 include not only the image data but a record of exactly how the image was acquired. To determine all the properties of the image (like exposure time, size, delay time, image type, comments, etc.), just double click on the image. Images can be false colored, converted to other graphic types, copied to the Windows clipboard, zoomed in to 300% or zoomed out to 25%, and directly printed. Many image filters are easily applied, including contrast maximization, 2D FFT, low/highband-pass filter, inelastic background subtraction, and more.
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