Thermal conductivity of a GaAs single crystal grown in microgravity

A comparative study of the thermal conductivity in the temperature interval 2–300 K is carried out for single-crystal GaAs samples grown on Earth and grown under analogous conditions in microgravity on the manned space station Mir. It is found that the heat transfer in the samples is due to phonons. A consistent processing of the temperature dependence of the thermal conductivity of the Earth-grown and space-grown samples is carried out in the framework of the Debye model of the phonon spectrum with allowance for boundary and resonant scattering and for scattering on “planar defects” and phonon–phonon U -processes. The difference in the behavior of the thermal conductivity space-grown and Earth-grown samples is due to the presence of excess arsenic in the Earth-grown sample, resulting in both resonant scattering and scattering on planar defects, which may be clusters of arsenic atoms.