Xiaoning Zhu

Ytterbium-pulsed fiber laser percussion drilling silicon for emitter wrap through solar cells

Different sidewall characters of the silicon microholes drilled with fiber laser pulses at 1065.2 nm were examined by a scanning electron microscope. It shows two different recast phases on the hole-wall: mild melt phase with smooth interface and vaporization phase with rough interface. These two recast phases show different etch rate when alkaline texturing, which sometimes leave some undesirable damages on the sidewall. After alkaline texturing, the taper holes transform into octagonal holes. And the eight sidewalls of the octagonal-hole alternating appear two different micro-nano structures, one is pyramid structure, the other is lamellar structure.