Combination of optical and X-ray techniques in the study of amorphous semiconductors under high pressure: an upgrade setup for combined XAS and XRD measurements

X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) are complementary techniques whose combination is a powerful tool of investigation of matter under extreme conditions (high pressure, high temperature). The standard setup at the ODE beamline (Soleil Synchrotron) has been modified in order to allow the performance of simultaneous XAS/XRD measurements on the same sample. These techniques, together with Raman spectroscopy measurements, were applied to the study of pressure-induced phase transitions of amorphous silicon-germanium alloy (a-SixGe1-x, with x=0.75) using a membrane diamond anvil cell as the pressure device.