We report on possibility to detect pulsed microwave radiation across the metal/oxide/porous silicon structures and analyse possible physical reasons causing the rise of the emf voltage signal. The n-type porous layers were fabricated according to conventional electrochemical etching procedure, and were exposed to pulsed 10 GHz microwave radiation. The results of investigation show that the porous Si samples have higher by at least one order voltage-to-power sensitivity than the samples without the porous layer, and are considered to have high potential to increase it further. Free carrier heating phenomenon is considered to be responsible for the signal formation.
We propose a new fast technique to determine thermal conductivity of a nanostructured material and demonstrate it for porous silicon. Transient thermoelectric voltage is measured after a pulsed laser irradiation, and analysis of the voltage decay time constant and porosity of the structure gives the value of the thermal conductivity. For n-type Si of 70% porosity we obtain the value of 35 W m-1 K-1 what is in good agreement with the results of other investigations The method can be easily applied for any other porous or otherwise structured low-dimensional materials.