Angular distribution of intensity of reflected radiation investigations of the influence of CO2 laser treatment on optical properties of hydrogenated amorphous silicon

Thin films of hydrogenated amorphous silicon (a-Si:H) were annealed using CO₂ laser radiation (λ=10.6 μm). Changes of optical properties of the treated a-Si:H were investigated using optical transmittance spectroscopy and the angular distribution of intensity of reflected radiation (ADIRR). The CO₂ laser annealing influences the spectral characteristics of the real part of refractive index n and absorption coefficient α of light in a-Si:H. This treatment increases the n and α values as well as the Urbach energy of a-Si:H. Simultaneously it decreases the optical energy gap of this material. The changes of optical parameters at the interfaces of a-Si:H–glass substrate and a-Si:H–air were established.