In取代Ga对GaSb的热电性能的影响

Effect of Substitution of In with Ga on Thermoelectric Properties of GaSb

通过在GaSb的Ga位进行等电子In取代以形成Ga/In间的原子质量波动和应力场波动,可散射短波声子从而降低锑化镓的晶格热导率。采用氧化硼助熔剂法成功制备了In_(x)Ga_(1-x)Sb(x=0,0.05,0.5)样品。研究结果表明In取代显著降低了GaSb的晶格热导率,其中50%的In取代使GaSb的室温晶格热导率由18 Wm^(-1)K^(-1)降低至4 Wm^(-1)K^(-1),最低晶格热导率达2 Wm^(-1)K^(-1)。此外,In取代同时也显著提升了GaSb的电性能,如In_(0.5)Ga_(0.5)Sb的室温电导率达15000 Sm^(-1),为锑化镓的6.8倍。由于电性能的提升和晶格热导率的下降,x=0.5样品具有最高热电优值,在775 K达0.44,显著高于锑化镓的最高热电优值(0.006)。

In this paper,we intend to scatter the short-wavelength phonons to reduce the lattice thermal conductivity of GaSb by the Ga/In atomic mass fluctuation and strain field fluctuation upon isoelectronic In substitution.The In_(x)Ga_(1-x)Sb(x=0,0.05,0.5)samples were successfully prepared by the B_(2)O_(3) flux method.The results demonstrate that the In substitution obviously reduced the lattice thermal conductivity of GaSb.The room temperature lattice thermal conductivity of GaSb was significantly reduced from 18 Wm^(-1)K^(-1)to 4 Wm^(-1)K^(-1)for Ga_(0.5)In_(0.5)Sb.And the smallest lattice thermal conductivity of 2 Wm^(-1)K^(-1)was obtained.Besides,the electrical properties were also enhanced by In substitution markedly,for example,the room temperature electrical conductivity of In_(0.5)Ga_(0.5)Sb reached 15000 Sm^(-1),6.8 times that of GaSb.A ZT_(max) of 0.44 was obtained at 775 K in the sample with x=0.5 due to the enhancement of electrical performance and reduction of the lattice thermal conductivity,obviously higher than that of GaSb(0.006).