An approach to control the Mg content in Sb-doped Mg₂Si via post annealing under different Mg partial pressures is developed. Annealing under low and high Mg partial pressures (≤ 1 × 10^–1 Pa and 1 × 10¹ Pa) result in low and high carrier concentrations of Mg₂Si_0.99Sb_0.01 (1.2 × 10²⁰ cm^–3 and 1.7 × 10²⁰ cm^–3) that correspond to a hypo-stoichiometric and a hyper-stoichiometric compositions, respectively. Mg₂Si_0.99Sb_0.01 with a hypo-stoichiometric composition shows a low figure of merit below 573 K mainly due to a reduction of the carrier mobility probably by the carrier scattering at Mg-deficient grain boundaries. The carrier mobility and the figure of merit are recovered by increasing the Mg content via annealing under high Mg partial pressure, which indicates that the annealing process is an effective way to recover the thermoelectric performance of Mg-deficient Mg₂Si-based materials.

提出了在不同的Mg分压下通过后退火控制Sb掺杂Mg ₂ Si中Mg含量的方法。在低和高Mg分压（≤1×10 ^–1  Pa和1×10 ¹  Pa）下进行退火会导致低和高Mg ₂ Si载流子浓度_0.99 Sb _0.01（1.2×10 ^{2 0}  cm ^–3和1.7×10 ²⁰  cm ^–3）分别对应于低化学计量组成和超化学计量组成。化学计量不足的Mg ₂ Si _0.99 Sb _0.01的品质因数低于573 K主要归因于载流子迁移率的降低，这可能是由于载流子在Mg不足的晶界处的散射所致。通过在高Mg分压下退火提高Mg含量可以恢复载流子迁移率和性能因数，这表明退火工艺是恢复缺Mg ₂ Si基材料热电性能的有效途径。