Transition metal monosilicide films on silicon for thermoelectronics and spintronics

Abstract

The growth of both monoclinic and cubic phases for ultrathin (UT) and thin FeSi and CrSi films and only cubic phase for CoSi on silicon was proven as confirmed by HRTEM. At temperatures of 2–30 K, shunting is absent for the UT films and the two-dimensional conductivity model is realized. In the temperature range of 2–30 K and magnetic fields of 0.25–8 T for the UT films: concentrations and type of majority carriers are determined; NMR and SMR regions are observed in FeSi and CoSi films; quantum MR model is realized in CrSi films at T = 2 K. Ferromagnetic loops and a superparamagnetic phase are observed in UT m-FeSi and c-CoSi films from 3 to 300 K. Temperature dependences of the power factor and ab initio calculations of the lattice thermal conductivity of nanowires made it possible to estimate ZT for FeSi and CoSi films as a function of temperature.