Investigation on the interface formation of ambient-pressure-dried SiO₂ aerogel film deposited on GaAs

The interfacial state between ambient-pressure-dried aerogel and GaAs has been examined with specific emphasis on the solvent of modification. Trimethylchlorosilane (TMCS), being widely used to modify aerogel, was shown to be inadaptable due to its constitutional chlorine, which formed HCl and then etched GaAs oxides on GaAs surface. The interface of GaAs with aerogel was roughly etched from the reflection of surface microstructure of aerogel. Therefore, surface modification of aerogel with TMCS induced a great damage to interfacial GaAs surface, resulted in the change of surface characteristics of GaAs, and finally induced cracks and a collapse of aerogel fractal structure. On the contrary, hexamethyldisilazane, another modifying agent for aerogel surface, represented a relatively good interfacial state, while aerogel could be successfully formed on GaAs substrate.