Thermoelectric properties of boron and boron phosphide CVD wafers

Electrical and thermal conductivities and thermoelectric power of p-type baron and n-type boron phosphide wafers with amorphous and polycrystalline structures were measured up to high temperatures, The electrical conductivity of amorphous boron wafers is compatible to that of polycrystals at high temperatures and obeys Mott's T-1/4 rule, The thermoelectric power of polycrystalline boron decreases with increasing temperature, while that of amorphous boron is almost constant in a wide temperature range, The weak temperature dependence of the thermal conductivity of BP polycrystalline wafers reflects phonon scattering by grain boundaries, Thermal conductivity of an amorphous baron wafer is almost constant in a wide temperature range, showing a characteristic of a glass, The figure of merit of polycrystalline BP wafers is 10(-7)/K at high temperatures while that of amorphous boron is 10(-5)/K. (C) 1997 Academic Press.