unusual properties. In particular, a wave functions modulation induced by insertion a thin barrier inside a quantum well may results in mobility enhancement [1-4]. In present report, the thermoelectric opportunities of PbTe/Pb1-x Eux Te DQW were estimated theoretically. The simplest case of (100) oriented structure, where all four ellipsoids of constant energy of bulk PbTe are equivalent and dimension quantization preserve the valley degeneracy, had been considered. The model of DQW with rectangular confinement potential and different well thicknesses d1 and d2 was considered. Potentials U of external barriers were assumed equal, and height U I of internal potential barrier was supposed equal or greater than U. The energies Eα of levels of dimensional quantization, wave functions, dispersion law and subbands populations were calculated as a function of inner barrier width b in symmetrical (d1 = d2 ) and asymmetrical structures. The structures with x=0.09 ( U, U I =173mev ) and x=0.11 ( U, U I =212mev ) and thin enough QWs, when isolated well contains one level of dimensional quantization, was examined. The coupling of such wells leads to doubling of levels if distance b between the wells is greater than some b* that depends on parameters of wells and barriers. The effect of barriers height increase on wave functions (WF) and on b* was investigated. Kinetic coefficients had been calculated on the base of Boltzmann equations, which were solved by iterations. The coupling of wells, the scattering on bulk acoustical and optical phonons, the carrier intrasubband and intersubband transitions, the multivalley character of bulk materials and nonpapabolicity of electron dispersion law were taken into account. The investigation of kinetic coefficients had shown that the structure with great distance b between wells is most promising for thermoelectric applications. Although, the maximum of mobility is achieved at b=b* and such structure has high thermoelectric power factor, the increase of Lorentz number in two levels system deteriorates thermoelectric figure of merit. Moreover, in considered structures, the peak of mobility is very narrow and the increase of barriers potential shifts it to smaller b (at d1=d1=20Å: b* = 18Å at U=173mev and b* = 9Å at U=212mev). The dependencies of thermoelectric figure of merit on electron concentration n are shown in Fig.1. The increase of density of state in low dimensional systems, and the presence of four equivalent valleys in considered structure provides high ZT. Maximal value of ZT is achieved in slightly asymmetrical structures (curves 1, 2), when levels of dimensional quantization are close to each other, and carrier intersubband scattering is suppressed due to redistribution of wave function between the wells. In strictly symmetrical structures (curves 3, 4), mobility is lower and ZT is lower too. The increase of x, and corresponding rise of barriers height leads to decrease of ZT, mainly, due to increase of effective masses and WF localization. In considered range of parameters, the increase of internal barrier height gives only a small reduction of ZT, and results of calculation are not shown here.figureFig. 1 Thermoelectric figure of merit ZT as a function of electron density n at T=300K, b=200Å. d1=19Å, d1=21Å – for curves 1, 2; d1=d1=20Å– for curves 3, 4; U=U I=173mev for 1, 3; U=U I=212mev for 2, 4.