At the Electrotechnical Laboratory the PIES (Pulverized and Intermixed Elements Sintering) method has been investigated in order to prepare mechanically strong and cost efficient materials and Ruthenium Sesquisilicide has been investigated in order to obtain high thermoelectric figure of merit above 1300K. The figure of merit values of p-type bismuth telluride based materials prepared by PIES method were the same as those of the commercial materials. In order to synthesize functionally graded thermoelectric materials by PIES method the temperature dependence of electrical properties of materials with different composition were clarified. Experiments on 10 doping elements were performed and we determined that phosphorous was the best candidate for n-type dopant which could achieve the optimum doping level.