在特定的气体氛围下,用一定能量密度的超短脉冲激光连续照射单晶硅片表面,制备出表面具有准规则排列的微米量级锥形尖峰结构的“黑硅”新材料。不同背景气体下的实验表明,激光脉宽和背景气体对表面微构造的形成起着决定性的作用。具体分析了SF6气体氛围中,皮秒和飞秒激光脉冲作用下硅表面微结构的演化过程。虽然两者均可造成硅表面的准规则排列微米量级尖峰结构,但不同脉冲宽度的激光与硅表面相互作用的物理机制并不相同。在皮秒激光脉冲作用下,尖峰结构形成之前硅片表面先熔化; 而飞秒激光脉冲作用下尖峰的演化过程中始终没有出现液相。对材料的光辐射吸收的初步研究表明,该材料对1.5～16 μm的红外光辐射吸收率不低于80%。

The new material “black silicon” formed by arrays of sharp conical spikes on the silicon surface is fabricated under the cumulative ultra-short laser pulses irradiation in different ambient atmospheres. The physical mechanisms of conical spikes evolutions impacting silicon surface under picosecond (ps) and femtosecond (fs) laser irradiations are different. The formation of spikes arrays depends on the pulse duration and ambient atmosphere. Especially, in SF6 ambient atmosphere, silicon surface micro-structuring evolutions under ps and fs laser irradiations are analyzed in detail. Under the ps laser irradiation, silicon surface is melted before the spike arrays formed; while under the fs laser irradiation, the formation of spike array does not go through the liquid phase. The preliminary experiment shows that the infrared radiation absorptance is more than 80% at the wavelength range of 1.5～16 μm.