Energy Relaxation Of Hot Electrons Research Articles

Hot Electron Relaxation in Quantum Wells

ABSTRACTHot electron relaxation in bulk semiconductors has been studied for several decades, but only through recent advances in crystal growth has it become possible to investigate the ther-malization of hot quasi-two-dimensional carriers in quantum wells. These same advances have opened the possibility of constructing various semiconductor devices which rely on hot electrons for their operation. We discuss experimental results on the energy relaxation of hot electrons in GaAs/AlGaAs quantum wells. The experiments make use of optical spectroscopy for determining the carrier distribution. In particular, steady-state hot photoluminescence measurements have been employed with modulation-doped quantum wells in order to minimally perturb the system by the photoexcited carriers. Both the relaxation of very energetic electrons and the cooling of a hot thermalized carrier distribution are considered. The quantum well results are compared to results from similar experiments with bulk GaAs.

A model for the origin of the oscillatory structure in the reverse bias J(V) characteristics of n+GaAs/(AlGa)As/n-GaAs/n+GaAs tunnelling devices

The oscillatory structure in the low-temperature reverse bias characteristics of n+GaAs/(AlGa)As/n-GaAs/n+GaAs tunnelling devices is explained in terms of the modulation of the resistivity of the undepleted region of the n- layer above the substrate by means of energy relaxation of hot electrons arriving from the high-field depletion layer beyond the barrier.

Hot electron energy relaxation in quantizing magnetic fields

A systematic study of the radiative recombination of hot electrons between Landau levels in several n-InSb samples has been carried out as a function of the free electron concentration and the applied electric and magnetic fields ( E ∼ H). The magnetic field range investigated was 0.5 to 3.0 T. Electron temperatures are derived in dependence of the total electric and the magnetic field applied. The carrier heating is impeded with increasing electron concentration and also with increasing magnetic field. From the direct observation of the recombination radiation intensity on electric field response the electron lifetime in the first Landau level is found to be less than 10 −8. The results obtained are discussed in light of a new theoretical approach. We give evidence that electron-electron scattering plays an important role both for the carrier distribution established and for the electron lifetime in the first Landau level.