^{1}

^{*}

^{1}

The properties of a ball-shaped semiconductor particles and metal particles with a semiconductor thin film on the surface thereof are established. So the dimensionless thermoelectric figure of merit of a material consisting of a large number of these particles is equal to 10 - 100.

The efficiency of the direct conversion of heat energy into electric current energy using solids is characterized by the dimensionless thermoelectric figure of merit of a material

In this paper we discuss the problem of a material with

We shall consider the thermoelectric properties of a material consisting of a large number of identical ball- shaped non-degenerate n-type semiconductor particles contacting each other and metal particles with a n-type semiconductor thin film on the surface thereof. The phonon component of the material’s thermal conductivity is zero as the point contact area is zero. This type of material has electronic thermal conductivity made possible by electron tunneling through the vacuum gaps between the particles near the point contacts. We shall calculate the Z parameter of this material. We shall simplify the task and assume that the particles make a simple cubical lattice, also we shall assume the material temperature Т = 300 - 800 K and the particles diameter d = 10^{−}^{6} - 10^{−}^{3} m.

We shall offer the following symbols:

is the potential barrier transparency coefficient for the electrons tunneling from particle into particle through the gap between them;

We shall compare the thermal conductivities k and

The electron fluxes through the contact region between two particles in the forward and backward directions coincide:

where

e is the elementary charge; k_{B} is the Boltzmann constant;

particle,

tion band bottom in the semiconductor;

Let electric potential gradient

If the condition

The heat flow

where

The heat flow caused by the radiative heat exchange between two particles by means of thermal radiation and

the radiant thermal conductivity of the material are then

respectively with

Let us assume that the space between the particles is filled with a dielectric. In this case the potential barrier _{p}, transferred by phonons through the contact area between two particles can be found using the formula:

where

Consider the thermoelectric properties of the material, consisting of a large number of identical spherical metal particles with a n-type semiconductor thin film on the surface thereof. We assume that the following conditions are met:

where

the semiconductor film [

vacuum gap between the two particles;

We now use the spherical coordinate system for the volume element

where

Expressions (1), (3), (7), (8), (9) and (11) - (20) were used to perform computer calculations of the values

Example of the calculated curves

We shall consider the thermoelectric properties of a material consisting of a large number of identical ball- shaped non-degenerate n-type semiconductor particles contacting each other. In the range of values

the values_{d} ≥ 1 W/m∙K), Z(χ) continues to decrease rapidly and monotonically.

In the range

(see, for instance,

Thus the currently existing semiconductor particles can be used to produce structures with the thermoelectric figure of merit Z = 10 - 100, if the thermionic work function of the particle surface ^{?5} m) is enlarged and

This work was supported by the Russian Foundation for Basic Research (project no. 12-02-97500) and the authorities of Orel oblast.