V. Yu. Kashirin

Peculiarities in the electron properties of δ〈Sb〉-layers in epitaxial silicon. III. Electron–phonon relaxation

Complex studies of weak electron localization, electron–electron interaction, and electron overheating in Si crystals containing a δ〈Sb〉-layer with various concentrations of Sb atoms are carried out in order to obtain information on the characteristic times of inelastic electron relaxation. The temperature dependence of the electron–phonon relaxation time τep derived from the electron overheating effect can be described by the dependence τep∝T−p, where p≅3.7±0.3, which corresponds to the case qTl<1 (qT is the wave vector of the thermal phonon and l the electron mean free path).

Low temperature electron transport inSi with an MBE grown δ -layer

The temperature alteration of the kinetic electron characteristics (conductivity, Hall coefficient, magnetic field dependences of resistivity) ofSi crystals containing δ-layers with variousSb atom concentrationsNSb has been studied in the range 1.6–300 K. It was revealed that at low temperatures the properties of such a system are specified by the δ-layer itself. The temperature dependence of the electronic characteristics of low resistance samples (NSb=(1÷3)·1014cm−2) is due to quantum interference effects (effects of electron weak localization (WL) and electron-electron interaction (EEI)) in the two-dimensional system, and those of high resistance (NSb=(5÷10)·1012cm−2) to hopping conductivity mechanisms. In the higher temperature range their behaviour is described by the properties of the doped semiconductor.

Weak localisation and interaction of electrons in MBE δ -layers inSi

Temperature (1.6–20K) and magnetic field (up to 2.5T) dependences of quantum corrections to the conductivity and Hall coefficient ofSi epitaxial films containing a δ-layer of different sheet densityNSb are studied. The quantum corrections are due to the effects of electron weak localization (WL) and electron-electron interaction (EEI). Analysis of the quantum corrections made it possible to determine the temperature dependence of electron phase relaxation time τϕ, the spin-orbit interaction time τ80 and the screening factorF. It is found that the dependence τϕ(T) is determined by the electron-electron scattering processes, τϕ∝T−p withp≈1, and an increase in the parameterF with decreasing electron concentrationn in the δ-layer is related to the specific features of the screening processes in two-dimensional electron systems.

Electron-phonon interaction in bismuth thin films

Abstract The behaviour of the electron weak localization effect in bismuth thin films (∼100A˚) under the conditions of electron overheating was investigated. The temperature dependences of the time of electron relaxation inelastic process during heating were obtained from the magnetic field dependences of the quantum corrections to conductivity, and the temperature dependence of the electron-phonon scattering time was found from the electron overheating.