Dear Colleagues
I am very confused about thermal conductivity (TC) value of crystalline silicon. The value I have found is around 148 W/m-K. But when I am comparing it with chromium (Cr), which is a metal having tTC 93 W/m-K, I do not understand how TC of Si can be higher than Cr. Could anyone please help me out with this?
Thanks
Parvez
Dear Abu Naushad Parvez,
Thermal conductivities of different materials can be measured at different temperatures. I guess that's the root of your confusion.
Hi Abu,
There is no contradiction in the fact you mentioned!
Good dielectric crystals may easily have better thermal conductivity than some metals, - through their lattice vibrations only, even without the contribution from free electrons.
The best example is diamond, just have a look at its specs.
Measurements on single-crystal silicon show that the thermal conductivity varies nearly as T−1, from 1.25±0.19 w/cm C° at 30°C, to 0.46±0.07 w/cm C° at 425°C. The series comparative method employed reduces errors due to radiation, thermocouple calibration, and contacts. The charged-carrier contribution to the conductivity is less than 1% at 425°C. The lattice conductivity is discussed in terms of phonon-phonon scattering at 425°C and in terms of isotope and phonon-phonon scattering at 30°C.
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