The Thermal Conductivity Tensor of β-Ga2O3 from 300 to 1275 K

Laser-flash measurements of the thermal conductivity lambda((hkl)) of Czochralski-grown beta-Ga2O3 single crystals are reported perpendicular to four independent crystallographic lattice planes (hkl) = ((2) over bar 01), (0 (1) over bar0), (00 (1) over bar), and (100) between room temperature and 1200 K. lambda. is represented by a symmetric tensor of rank 2 and has four independent components. Tensor components lambda(11) = lambda((100)) = 12.13 W m(-1) K-1 and lambda(22) = lambda((010)) = 24.26 W m(-1) K-1 (values for 300 K) can be directly measured lambda(33) = 14.09 W m(-1) K-1 and lambda(13) = -0.992 W m(-1) K-1, instead, are obtained by combining lambda((001)) = 13.53 W m(-1) K and lambda(((2) over bar 01)) = 14.33 W m-1 K. The crystallographic (b) over right arrow -axis is the direction with the highest thermal conductivity, lambda(22). The thermal conductivity assumes its lowest value (11.73 W m(-1) K-1) in a direction close to the crystallographic (a) over right arrow -axis. However, this direction does not coincide with (a) over right arrow, and changes with temperature.

Automated summary

This paper presents laser flash measurements of the thermal conductivity of Czochralski-grown beta-Ga2O3 single crystals along different crystallographic lattice planes. The results show that the thermal conductivity has orientation dependence and varies with temperature.