E.L. Shangina

Quantum corrections to the conductivity and quantum Hall effect in GaAs‐GaAlAs multiple quantum well structures

The magnetotransport properties of GaAs‐GaAlAs multiple quantum well structures, with widths of the quantum wells Lw=33–66 A, have been investigated over a wide temperature and field range. The variation of the electron mobility with Lw (and temperature) can be accounted for by interface roughness scattering. A negative magnetoresistance was observed. An analysis within the theory of weak localization allowed us to evaluate the relaxation time of the phase of the electronic wave function and its temperature dependence τφ(T). Measurements in high‐magnetic fields (up to 40 T) at T=4.2 K revealed pronounced Shubnikov‐de Haas oscillations and the quantum Hall effect.

Nonequilibrium lateral photoconductivity of GaAs/AlxGa1−xAs quantum-well superlattices at low temperature

The photoconductivity of GaAs/AlxGa1−xAs (x=0,36) superlattices grown by molecular beam epitaxy have been investigated at T=77K. It was found that the photocurrent relaxes to “dark” current-volt characteristics j(V) even in the case of temporally constant sample illumination. The heating from 77 K to 293 K leads to the restoring of original light characteristics. The photocurrent dependence on time j(t) consists of several exponent with Г=5–50 c. Phenomenon was explained by re-charge of DX-centers in barriers. Peaks associated with those impurities were found in the low temperature photoluminescence spectrum.

Quantum corrections to conductivity and quantum hall effect in GaAs-GaAlAs multiple quantum well structures

Abstract We report on an investigation of the galvanomagnetic properties of GaAs-GaAlAs superlattices. The results can be explained in terms of interface roughness scattering of electrons in quantum wells.