Modulated free-carrier absorption in silicon - a spectroscopy approach

In the paper, an analysis of the spectral characteristics of the MFCA (modulated free-carrier absorption) signal for silicon 3-5 cm, n-type is presented. During the change of the wavelength of a probe light, three distinctive regions are observed in the amplitude and the phase characteristics. In the first region ((probe)<<hc/E-g), only the PCR (photocarrier radiometry) signal exists. The second region ((probe)>hc/E-g) is typical for the MFCA signal. The nature of the third region ((probe) near hc/E-g), characterized by a long relaxation time is being studied here. The spectroscopy approach to the MFCA technique provided an opportunity to explain the type of free-carrier scattering mechanism that dominates in the NIR region. In the paper, an attempt was also undertaken to estimate the recombination parameters of the sample. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim