多孔硅有效介电函数研究

Effective Dielectric Function of Porous Silicon

采用改进过的Maxwell-Garnett模型研究了入射光波长和多孔硅的孔隙率对反射光谱和介电光谱的影响,结果表明:(1)随着入射光波长的增大,多孔硅的反射率先增大后减小,而随着孔隙率的增大反射光谱出现了明显的下塌趋势,且孔隙率越大下塌得越明显;(2)随着孔隙率的增加,多孔硅复介电光谱出现明显的蓝移现象,且多孔硅有效介电常数的实部和虚部均变小。此外还对这种现象给出了较为合理的解释。

By using the modified Maxwell-Garnet model, the influences of porosity and incident light wavelength on reflective and dielectric spectra of porous silicon have been investigated. It is found that： （1） the reflective index is firstly enhanced and then reduced with the increase of incident wavelength, and the reflective spectrum exhibits a tendency of collapse with the increase of porosity; （2） the porous silicon dielectric spectrum is blue-shifted and the real and imaginary parts are reduced with the increase of porosity. These phenomena are reasonably explained.