SiGe:GaP合金的微观结构和温差电特性

经高温热处理后的 SiGe∶GaP 半导体温差电材料,其微观结构由具有富 Si 相特征变化成为具有富 Ge 相特征,温差电优值也得到了提高。实验还表明,材料晶格热导率的降低与富 Si 相的消失和富 Ge相的出现有关。然而,塞贝克系数和电导率的显著变化却与微观结构中富 Si 相和富 Ge 相的变化基本无关。通过对材料微观结构和温差电特性比较发现,具有富 Ge 相特征的微观结构对应于较大的温差电优值。

MICROSTRUCTURE AND THERMOELECTRIC PROPERTIES OF SiGe:GaP ALLOYS

An experimental investigation into the effect of heat treatment on morphologyand thermoelectric properties of SiGe:GaP alloys is reported.Attempt was made to correlate thechangas in the thermoelectric properties with these in matarial's morphology.The results indi-cate that a reduction in the lattice thermal conductivity of the alloys is partially attributed to thechanges in material's morphology,i.e.the appearance of Ge-rich regions and the disappearanceof Si-rich regions.However,no correlation has been found between the material's morphologyand the observed substantial changes in electrical properties of the alloys.Nevertheless,the ex-perimental results show that the alloys with a morphology consisting of only host matrix andGe-rich regions exhibit the largest thermoelectric figure of merit.