Effects of substrate nitridation time on the thermal properties of GaN films grown on silicon by molecular beam epitaxy

In this work the structural and thermal properties of GaN films grown on Si substrates with different nitridation times have been investigated. We found an optimal nitridation time for which the GaN crystal qualtity can be improved. On the other hand, effective thermal conductivity of the GaN/Si system was obtained using the photoacoustic technique and from these results the nitridation time dependence of the interface thermal conductivity can be evaluated using the two-layer model. The variation of the interface thermal conductivity for different nitridation times can be associated with the interface phonon scattering process by the presence of disorder at the interface of the GaN/Si heterostructure.