Infrared optical properties of aged porous GaAs

Aging properties of porous GaAs were investigated nondestructively using va riable angle of incidence infrared spectroscopic ellipsometry. In addition to the thickness and volume porosity, properties of the solid part of the p orous material are investigated in terms of the long-wavelength dielectric function and chemical composition. The high sensitivity is employed to dete ct and identify infrared resonant absorptions related to different vibratio n modes of cubic and amorphous As2O3. Resonances centered at 333.3, 480, 78 5.8, 838, and 1045.5 cm(-1) are from cubic As2O3, whereas resonances center ed at 350, 490, and 808.5 cm(-1) are from amorphous As2O3.