抄録
Si is a promising candidate for environmentally friendly thermoelectric (TE) material because of its non-toxicity
and abundance. However, the lattice thermal conductivity of Si is extremely high, leading to low dimensionless figure of merit ZT. In a previous study, Xie et al. succeeded in reducing lattice thermal conductivity and improving ZT (0.39 at 1073 K) by forming dense dislocations in CoSi2/Si composite. These dislocations were automatically introduced into Si matrix by sintering melt-spun powders. The formation mechanism of the dislocations is considered to be related to the eutectic reaction between CoSi2 and Si. In this study, we applied the same process to Cr-Si system, which has similar eutectic temperature and eutectic composition to Co-Si system, intending to get insight into the formation mechanism of the dislocations. P-doped n-type Si and CrSi2 nanocomposites were synthesized by melt spinning followed by spark plasma sintering. Transmission electron microscope observation showed that there were dislocations in Si matrix that seems to be formed by the same mechanism with CoSi2/Si. Owing to the reduced lattice thermal conductivity, the maximum ZT reached 0.37 at 1073 K. This result indicates that a eutectic reaction plays an important role in the formation of the dislocations.
