A. V. Butenko

Electric-field-effect thermoelectrics

A significantly large thermoelectric “figure of merit” in a bipolar semiconductor is achieved by converting it, by doping, into an essentially monopolar semiconductor. We show here, that for a bipolar semiconductor film, having a thickness smaller than the screening length, there is an alternative to doping to obtain a practically monopolar semiconductor. The electric-field effect (EFE) or the ferroelectric-field effect can be used to quench the concentration of one type of charge carriers. We show that this method is particularly suited for narrow-gap semiconductors and for semimetals, having sufficiently high dielectric permittivity. We also show that this “EFE doping” is free from the drawbacks of conventional doping. Our analysis demonstrates that increased values of the figure of merit are feasible. We present here the theory and the figure-of-merit calculation for typical cases of the bipolar semiconductor thermoelectric film under EFE doping. Numerical results for a film of the PbTe type are presented.

CHARACTERIZATION OF THE ELECTRICAL PROPERTIES OF SEMIMETALLIC BI FILMS BY ELECTRICAL FIELD EFFECT

The electrical field effect (EFE) was used to investigate and to characterize the electrical properties of Bi films. The samples were prepared in a capacitor configuration with Al as the gate electrode, Al2O3 as the dielectric and the thin (∼1300 A) thermal-evaporation deposited Bi film sample serving as the other electrode. The dependence of EFE on the electrical field (up to electrical displacements ∼107 V/cm or ≈1013[e]/cm2 “surface” charge) and on temperature (15–300 K), and also the temperature dependence of Hall constant, were determined. The experimental results are shown to be consistent with the EFE theory of a semimetal film, assuming that: (1) the film has an interface “dead layer” (∼600 A) that does not contribute markedly to EFE due to its extremely low carrier mobilities. Only in the rest, “good” part of the film, the electroconductivity is modulated and leads to a measurable EFE; (2) the temperature behavior of EFE follows the temperature dependence of the electron and hole mobilities and i...

Raman scattering and electrical resistance of highly disordered graphene

Raman scattering (RS) spectra and current-voltage characteristics at room temperature were measured in six series of small samples fabricated by means of electron-beam lithography on the surface of a large size

Hall constant in quantum-sized semimetal Bi films: Electric field effect influence

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The cause of the anomalously small electric field effect in thin films of Bi

industrial monolayer graphene film. Samples were irradiated by different doses of

Effect of annealing on Raman spectra of monolayer graphene samples gradually disordered by ion irradiation

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Highly resistive p-PbTe films with carrier concentration as low as 1014 cm−3

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Characterization of high-temperature PbTe p-n junctions prepared by thermal diffusion and by ion implantation

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Resistance asymmetry of a two-dimensional electron gas caused by an effective spin injection

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