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利用800 nm波长的飞秒抽运探测技术测量了具有不同单晶硅薄膜厚度的绝缘衬底上硅(SOI)皮秒瞬态反射率变化,并通过基于受激载流子密度和温度变化过程建立的反射率模型讨论了SOI表面载流子的超快动力学过程。研究表明,表面复合速度(SRV)是影响载流子动力学响应的主要因素,且薄膜厚度越小表面复合速度就越大,对应的表面态密度可达到10~(15)cm~(-2)。对于较小的SRV,受激载流子的超快响应决定了瞬态反射率变化;而对于较大的SRV,晶格温升对瞬态反射率变化的贡献变得显著,使得反射率在更短的时间内恢复并超过初始值。
The instantaneous picosecond transient reflectivity of silicon on SOI with different thickness of monocrystalline silicon thin films was measured by using femtosecond pumping detection technology at 800 nm wavelength. Based on the density and temperature change of stimulated carriers The established reflectivity model discusses the ultrafast kinetics of charge carriers on SOI surfaces. The results show that the surface recombination velocity (SRV) is the main factor affecting the dynamic response of the carrier. The smaller the film thickness, the larger the surface recombination speed, and the corresponding surface state density can reach 10 ~ (15) cm ~ (-2) ). For smaller SRVs, the fast response of stimulated carriers determines the transient reflectivity change, whereas for larger SRVs, the contribution of the lattice temperature rise to the transient reflectivity becomes significant, making the reflectivity at Restored and exceeded the initial value in a shorter period of time.