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In-situ X-Ray Diffraction

As a distinctive experimental feature, PDI owns three special MBE chambers that allow the in-situ, real-time analysis of growth processes by x-ray diffraction. These chambers can be connected to our own beamline at the synchrotron BESSY II, Helmholtz-Zentrum Berlin für Materialien und Energie. Complementary x-ray diffraction measurements are performed at the synchrotron sources PETRA III and ESRF.

  • PHARAO1: currently not in use
  • PHARAO2: Ge-Sb-Te phase-change materials
  • PHARAO3: semiconducting oxides (connected to beamline)

The PHARAO facility is used for in-situ x-ray diffraction measurements to investigate epitaxial layers during molecular beam epitaxy (MBE) growth. It consists of the beamline, the diffractometer, and three plug-in MBE machines that can be swapped in and out of the diffractometer. Our beamline U125/2-KMC at BESSYII is located at the direct line of an U125 undulator source. It consists of a collimating mirror, a constant-exit Si(111) double-crystal monochromator (DCM), as an alternative a double multilayer monochromator (DMM) and a refocusing mirror. The DCM offers an energy range from about 5 to 15 keV with an energy resolution DE/E of around 2*10-4. The DMM has been added in 2008. It works at a fixed energy of 10 keV with an energy resolution around 1%, thereby offering an about 50 times higher primary beam intensity.