For the hydrodynamic (HD) transport model used in this work the
current densities are obtained for electrons as:

and for holes:

Comparing to the DD approach the carrier temperature can deviate from the lattice temperature . The conservation of the average energy is written:

The energy fluxes are defined as:

and denote the average carrier energies, the equilibrium energies. The are approximated as:

The first term represents the carrier thermal energy while the second denotes the carrier kinetic energy. In this work the carrier kinetic energy is neglected against the thermal energy. Some publications name the simplified transport model an energy transport model. The impact of this simplification, which goes along with a limited number of moments considered for the solution of the Boltzmann equation, and the results for device application from both numerical and accuracy aspects are discussed in Section 3.6. The carrier thermal conductivities are defined for electrons:

and for holes:

(3.14) and (3.15) represent a generalized

2001-12-21