Dear Deena,
I found these values in the book "Handbook on Physical Properties
of Ge, Si, GaAs and InP" by A. Dargys and J. Kundrotas.
specific heat of GaAs: 0.33 J/(g.K)
Thermal conductivity: 0.58 W/(cm.K)
both are values at room temperature.
Debjani
Research Scholar (Semiconductor Group)
Department of Physics Ph: (080)309-2316
Indian Institute of Science Fax:(080)334-1683
Bangalore - 560012