The acoustoelectric effect in a semiconductor superlattice (SL) has been studied for a hypersound in the region ql>>1 (where q is the acoustic wave number and l is the electron mean free path). A nonlinear dependence of the acoustoelectric current jac on the constant electric field E is observed. It is noted that when the electric field is negative the current jac rises, reaches a peak and falls off. On the other hand, when the electric field is positive the current decreases, reaches a minimum and then rises. A similar observation has been noted for an acoustoelectric interaction in a multilayered structure resulting from the analysis of Si/SiO2 structure. The dominant mechanism for such a behaviour is attributed to the periodicity of the energy spectrum along the SL axis.

An investigation of laser stimulated thermopower in chiral CNT is presented. The thermopower of a chiral CNT is calculated using a tractable analytical approach. This is done by solving the Boltzmann kinetic equation with energy dispersion relation obtained in the tight binding approximation to determine the electrical and thermal properties of chiral carbon nanotubes. The differential thermoelectric power along the circumferential α cz and axial α zz are obtained. The results obtained are numerically analyzed and α is found to oscillate in the presence of laser radiations. We have also noted that Laser source above 4.6 x 10 7 V/m lowered the thermopower otherwise there is no change. Varying ∆ s and ∆ z the thermopower changes from positive to negative.

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