Study of Three-Subband Electron Mobility in AlGaAs Based Semi-Non-Square Quantum Well Structures

We study the effect of semi-non-square potential profiles, such as semi-parabolic (SP) and semi-cubic (SC) on multisubband electron mobility under the influence of externally applied electric field <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$F$</tex> in AlxGal-xAs based quantum well (QW) structures. Here, different scattering mechanisms are taken for computation of such as ionized impurity (ii-) and alloy disorder (al-) producing mobilities and ual. A maximum of three subband occupancy is achieved. Interestingly, as <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$F$</tex> enhances from -20 kV/cm, increases with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$F$</tex>, showing step-like increments at the subband transitions. However, decreases with an increase in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$F$</tex> during double and single subband occupancy. The results show that <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$u$</tex> (SCQW) > <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$u$</tex> (SPQW) for all values of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$F$</tex> This is mainly due to the dominance of al-scattering in SPQW compared to SCQW. Additionally, the increased number of occupied subbands introduces more scattering channels in QW, significantly affecting <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$u$</tex>.