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DF: Dielektrische Festkörper

DF 2: Elektrische und optische Eigenschaften II

DF 2.6: Fachvortrag

Montag, 26. März 2001, 16:50–17:10, S18/19

Optical characterisation of silica xerogels — •C. Himcinschi¹, C. Murray², M. Friedrich¹, I. Streiter², S. Schulz², T. Gessner², and D.R.T. Zahn¹ — ¹Institut für Physik, TU Chemnitz, 09107 Chemnitz, Germany — ²Zentrum für Mikrotechnologien, TU Chemnitz, 09107 Chemnitz, Germany

Silica xerogel films on Si(100) substrates were prepared using an acid catalysed sol-gel method. The films were spun on and gelated in a solvent atmosphere before being dried. Annealing and hexamethyldisilazane (HMDS) hydrophobisation were then carried out. The optical constants and the thicknesses of the films were determined after each preparation step using variable angle spectroscopic ellipsometry (VASE). The chemical composition of xerogel films was determined from infrared (IR) spectroscopy. The evolution of the IR bands which correspond to absorption by bonded hydroxyl groups (Si-OH) and adsorbed water show that hydrophobisation of the films occurs after HMDS treatment. The changes in the refractive indices are correlated with changes in the chemical structure.