Work

Au and B co-doped p-type Si-Ge nanocomposites possessing ZT = 1.63 synthesized by ball milling and low-temperature sintering

Year: 2019

Type: article

Abstract: The enhanced value of the dimensionless figure of merit was achieved in a P-type Si-Ge alloy containing a small amount of Au and B, Si 0.62 Ge 0.31 B 0.03 Au 0.04 . After the 6 h ball milling, the sample was sintered at 873 K under 400 MPa with a soaking time of 4 h. The precipitation of (Au) occurred in Si-Ge alloy matrix. The large Seebeck coefficient of 464 μ VK −1 was achieved at 973 K, which might be due to the sharp peak, that consists mainly of 5 d states of Au, near the top of the valence band in the electronic density of states. Assisted by the values of electrical resistivity ∼10 mΩcm and thermal conductivity 1.5 Wm −1 K −1 , the large Seebeck coefficient led to a value of ZT exceeding 1.6, which is much higher than that of previously reported Si-Ge-based composites.

Source: Japanese Journal of Applied Physics

DOI: 10.7567/1347-4065/ab4fb9