Electron transport and optical properties of shallow GaAs/InGaAs/GaAs quantum wells with a thin central AlAs barrier

Abstract

Shallow GaAs/InGaAs/GaAs quantum well structures with and without a three monolayer thick AlAs central barrier have been investigated for different well widths and Si doping levels. The transport parameters are determined by resistivity measurements in the temperature range 4-300 K and magnetotransport in magnetic fields up to 12 T. The (subband) carrier concentrations and mobilities are extracted from the Hall data and Shubnikov-de Haas oscillations. We find that the transport parameters are strongly affected by the insertion of the AlAs central barrier. Photoluminescence spectra, measured at 77 K, show an increase of the transition energies upon insertion of the barrier. The transport and optical data are analyzed with help of self-consistent calculations of the subband structure and envelope wave functions. Insertion of the AlAs central barrier changes the spatial distribution of the electron wave functions and leads to the formation of hybrid states, i.e. states which extend over the InGaAs and the delta-doped layer quantum wells.

Hot electron transport in heterostructures

“…In particular, ternary alloy AlGaAs/GaAs, InAlAs/InGaAs and AlGaAs/InGaAs heterostructures are important for application in high electron mobility transistors (HEMTs). The transport of electrons with high mobility in a HEMT channel is still the subject of many investigations [2][3][4][5][6].…”

Особенности ионизации доноров кремния и рассеяние электронов в псевдоморфных квантовых ямах AlGaAs/InGaAs/GaAs при сильном одностороннем delta-легировании

“…При слабом легировании µ H (n H ) возрастает, а затем при увеличении легирования убывает. Для анализа наблюдаемого характера µ H( n H ) был проведен расчет подвижности электронов в двухподзонном приближении при рассеянии на удаленных ионах примеси с учетом самосогласованных профилей электронных волновых функций [12]. Результаты расчета (представлен-ные на рис.…”

Electron mobility in the GaAs/InGaAs/GaAs quantum wells

“…It could be achieved by inserting a delta layer of impurities in the plane of the well. We do not know publications concerning systematic investigations of mobility in such samples, except of a few measurements for the systems of AlGaAs/GaAs/AlGaAs [6], InAlAs/InGaAs/InAlAs [7,8] GaAs/InGaAs/GaAs [9]. Therefore, the purpose of this work was to investigate temperature dependences of the conductivity and Hall mobility of electrons within the range 4 to 400 K in the GaAs/InGaAs/GaAs quantum wells with different concentrations of deltadoping impurity in the well plane.…”