Thermal Conductivity of InGaAs/InGaAsP Superlattices measured with 3ω Method

The thermal conductivity of InGaAs/InGaAsP superlattices with different periods was measured from 100 K to 320 K using 3ω method. For all the superlattices, the thermal conductivity was found to decrease with temperature increase. For the superlattice with different periods, when the period thickness is smaller than the mean free path (mfp) of phonons, the thermal conductivity was found to decrease with a increase in period thickness and exhibit a minimum at certain period. But the thermal conductivity was found to increase monotonically with the increasing period thickness when the period is longer than the mfp, which implies that the interface thermal resistance dominated in phonon transport in this case. The experimental and theoretical results show that, with the increase in period thickness, the dominant mechanism of phonons transport in superlattices will shift from wave theory to particle theory, which is critical for the cutoff of phonons and will be a foundation for the design of superlattice structures