Reduced thermal conductivity in low-temperature-grown GaAs

Thermal conductivity of low-temperature-grown GaAs(LT GaAs) was measured at room temperature using a self-heated photolithographically patterned platinum wire on the surface of the sample. Finite element calculations were performed to extract the thermal conductivity from the nonlinear I-V characteristic of the wires. For LT GaAs grown at a substrate temperature of 240 degrees C, the thermal conductivity was found to be only 23% of the value for stoichiometric GaAs. Rapid thermal annealing of the sample at 650 degrees C for 30 s increased the thermal conductivity to 46% of the GaAs value. Strong phonon scattering by point defects could account for reduced thermal conductivity in the as-grown material. The reduced thermal conductivity in the annealed material, however, is not consistent with our current understanding of the defects in annealed LT GaAs. (C) 1999 American Institute of Physics. [S0003-6951(99)01516-8].