Heat transfer in nanostructures differ significantly from that in the bulk materials since the characteristic length scales associated with heat carriers, i.e., the mean free path and the wavelength, are comparable to the characteristic length of the nanostructures. Nanostructure materials hold the promise of novel phenomena, properties, and functions in the areas of thermoelectric energy conversion and micro/nano electronic devices. One of the major challenges in micro/nano electronic devices is to study the ‘hot spot’ generation by accurately modeling the carrier-optical phonon-acoustic phonon interactions. Thermoelectric properties are among the properties that may drastically change at nanoscale. During the last decade, advances have been made in increasing the efficiency of thermoelectric energy conversion using nanostructures. In this paper, the non-equilibrium interaction between carriers and phonons in semiconductor thin films is modeled using the Boltzmann transport model (BTM) for studying the transient characteristics of coupled energy transport. The role of nanocomposites in improving the thermal efficiency of thermoelectric devices is also studied by applying the Boltzmann Transport Equation for modeling thermal transport in nanocomposites. The results of this numerical study can help in identifying efficient nanocomposite configuration for use in thermoelectric devices and in understanding ‘hot spots’ in micro/nano electronic applications. The future scope of extending the present models to study problems of increasing complexities in nanoscale energy transport is also discussed.