ИСТИНА

The perspectives of amorphous silicon (a-Si) films employment as a basis for heterojunction solar cells and waveplates are demonstrated. The possibility to achieve surface crystallization of the 1 μm-thick a-Si film with crystalline layer thickness of 45±5nm is demonstrated by depth-resolved Raman spectroscopy and optical microscopy, when the irradiating laser fluence of 0.1 J/cm2 is used, which is lower than a-Si ablation threshold. The electrical measurements indicate formation of a heterojunction between nanocrystalline Si and a-Si phases in such samples. Femtosecond laser irradiation of a-Si films with fluence of 0.15 J/cm2 leads to formation of LIPSS with low spatial period and optical retardance of 280±40 nm.