We explore the efficiency of a thermoelectric energy converter constituted by a Si/Ge nanowire of length L. A constitutive equation of thermal conductivity as function of composition and temperature is derived in accordance with experimental data obtained at the constant temperatures \(T=300\,\hbox {K}\), \(T=400\,\hbox {K}\), and \(T=500\,\hbox {K}\) by a nonlinear regression method. A thermodynamic model of thermoelectric energy converter is developed in accordance with second law of thermodynamics. Then, we investigate the thermoelectric efficiency of such system as function of the composition, and of both composition and temperature gradients applied at its ends. For each temperature, we calculate the values of composition and heat conductivity giving the optimal efficiency of the thermoelectric energy conversion. A series of constraints on the material functions entering the model equations, which are necessary and sufficient to guarantee the optimal efficiency of the system, are determined and discussed.

我们探索由长度为L的Si / Ge纳米线构成的热电能量转换器的效率。根据在恒定温度\（T = 300 \，\ hbox {K} \），\（T = 400 \，\ hbox {K }下获得的实验数据，导出了热导率随组成和温度变化的本构方程。} \）和\（T = 500 \，\ hbox {K} \）通过非线性回归方法 根据热力学第二定律建立了热电换能器的热力学模型。然后，我们研究了该系统的热电效率，该热电效率取决于组成，在其末端施加的组成和温度梯度的函数。对于每个温度，我们计算组成和热导率的值，从而给出热电能量转换的最佳效率。确定并讨论了对进入模型方程的材料函数的一系列约束，这些约束对于保证系统的最佳效率是必要的和充分的。