IR-reflection study of sintered SiC:Al thermoelectric semiconductors

IR-reflection spectra of sintered SiC:Al thermoelectric semiconductor samples are studied in its reststrahlen region and analysed using a 4-component effective medium model. The effects of Al impurities 1) reducing the pores, 2) increasing electrical conductivity and 3) acting as metallic inclusions, can be observed by the change of reflectance in and outside of the resonance, and that these effects can be separated by the proposed effective medium model. These results combined with the possibility of local probing offers a versatile means to characterize the quality of sintered samples, especially of thermoelectric semiconductors.