Topics in Present-day Science Technology and Innovation: Ultrafast Relaxation Processes in Semiconductors

Abstract

The nowadays notable development of all the modern technology, fundamental for the progress and well being of world society, imposes a great deal of stress in the realm of basic Physics, more precisely on Thermo-Mechanical Statistics. In electronics and optoelectronics we face situations involving physical-chemical systems far-removed-from equilibrium, where ultrafast (in pico-and femto-second scale) and non-linear processes are present. Here we describe in an extended overview the question of ultrafast relaxation processes in the excited plasma in semiconductors.

Hot-phonon effects in photo-excited wide-bandgap semiconductors

“…The excess energy is transferred via various scattering processes to the lattice (phonons) [11]. This transient relaxation is characterized by quasi-temperatures T and chemical potentials μ that determine the corresponding Fermi-Dirac (carriers) and Bose-Einstein distributions (phonons), respectively [3,12]. Often, only two temperatures (carriers and phonons) are employed which neglects their spectral dispersion, but consideration of different phonon branches is mandatory for a useful physical description [8,9].…”