Layer-by-layer deposition of MnSi1.7 film with high Seebeck coefficient and low electrical resistivity

• MnSi1.7 films are deposited layer by layer by a short time interruption of film deposition.
• The thickness of each MnSi1.7 layer can be controlled in the nano-scale.
• MnSi1.7 films have a higher Seebeck coefficient and a lower electrical resistivity.
• The quantum size effect in n-type MnSi1.7 films is rather strong.

A good thermoelectric material should have a high Seebeck coefficient, a low electrical resistivity, and a low thermal conductivity. For conventional thermoelectric materials, however, increasing the Seebeck coefficient also leads to a simultaneous increase in the electrical resistivity. In this paper, a method of layer-by-layer deposition of MnSi1.7 film with high Seebeck coefficient and low electrical resistivity is developed. After deposition of the first MnSi1.7 sub-layer, the deposition process is interrupted for several minutes, and then continues for another MnSi1.7 sub-layer. Therefore, the MnSi1.7 film contains two sub-layers for one interruption, three sub-layers for two interruptions, and so on. It is found that the n-type MnSi1.7 film with two sub-layers has a higher Seebeck coefficient, −0.451 mV K−1, and a lower electrical resistivity, 19.4 mOhm-cm, at 483 K as compared to that of without deposition interruption, −0.152 mV K−1 and 44.3 mOhm-cm. The p-type MnSi1.7 film with three sub-layers also has a higher Seebeck coefficient, 0.238 mV K−1, and a lower electrical resistivity, 5.5 mOhm-cm, at 733 K in comparison with that of without deposition interruption, 0.212 mV K−1 and 10.4 mOhm-cm.