Thermoelectric performance of copper-rich β-Cu2Se films with Ag -doping by magnetron sputtering

The concept of phonon-liquid electron-crystal (PLEC) have attracted many researchers for thermoelectric materials. In this study, a series of Ag-doped beta-Cu2Se films were prepared on single crystalline Si(111) substrate by magnetron sputtering and the influence of Ag doping on the phase composition, chemical component and thermoelectric performance of the deposited beta-Cu2Se films were studied. An energy dispersive spectrometer (EDS) showed that the Cu-rich beta-Cu2Se films in which the ratio of Cu to Se in beta-Cu2Se lattice varied from 3.59 to 4.96 as Ag atomic percent content increased from 0 to 2.97 were obtained. The Ag existed in the form of CuAgSe phase which increased electrical resistivity and Seebeck coefficient. The phase transition from a to 8 phase of Cu2Se only took place at similar to 60 degrees C. The variation of electrical resistivity with Ag content relied on the combined action of the amounts of CuAgSe phase and the ratio of Cu to Se in beta-Cu2Se lattice of deposited films. The power factor of 1.37 at% Ag samples at whole measured temperature was the highest in all samples due to high Seebeck coefficient. It was attributed to lower resistivity than that of bulk Ag-doped beta-Cu2Se materials of references that the power factor of our deposited films reached the order of mW.m(-1)K(-2).

Automated summary

In this study, a series of Ag-doped beta-Cu2Se films were prepared and the impact of Ag doping on the phase composition, chemical component, and thermoelectric performance of the deposited films was investigated. The presence of Ag resulted in the formation of the CuAgSe phase, increasing electrical resistivity and Seebeck coefficient. The power factor reached its peak in the 1.37at% Ag samples due to a combination of high Seebeck coefficient and low resistivity compared to bulk Ag-doped beta-Cu2Se materials.