Structural properties of solution processed Ge23Sb7S70 glass materials

Solution-processing of chalcogenide glass materials has many benefits for the fabrication of photonic devices. We report on the structural properties of Ge23Sb7S70 glass during solution-processing. The molecular and micro-structure of the bulk glass and the n-propylamine solution, as well as the spincoated thin films and post-irradiated films are analyzed by Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. We find the vibrational spectral fingerprint of Ge4S10 4 -units in the amine solutions as well as in the spin-coated films, indicating a similar molecular structure of solutions and solution-processed films, which differs from the bulk glass. Moreover, the spin-coated films exhibit nanopores, and change their composition during irradiation such that sulfur escapes from the film while oxygen gets absorbed.