title: Doping effects on ablation enhancement in femtosecond laser irradiation of silicon.
abstract: We have conducted an experimental investigation on highly efficient femtosecond laser micromachining of silicon through N-type doping. We found that the material removal amount has a close relationship with the doping concentration rather than with the doping types. The amount of material removal was enhanced gradually as doping densities increased. When the doping density reached higher than 10(18) cm(-3), the ablation threshold was considerably reduced, up to 15%-20%. The results of the experiment indicate that the high density of initial free electrons by doping is the fundamental reason for efficiency improvement, and bandgap shrinkage also plays an important role. The electrons are excited more easily from the valance band to the conduction band and acquire higher initial kinetic energy, which then promotes the material ablation process.
authors: Juqiang
authors: J
authors: Fang
authors: Lan
authors: L
authors: Jiang
authors: Qiang
authors: Q
authors: Cao
authors: Kaihu
authors: K
authors: Zhang
authors: Yanping
authors: Y
authors: Yuan
authors: Yongfeng
authors: Y
authors: Lu
mesh_terms: D007834:Lasers; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D011829:Radiation Dosage; D012825:Silicon / Q000737:chemistry* / Q000528:radiation effects*; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D012825:Silicon