Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8149652 | Journal of Crystal Growth | 2015 | 6 Pages |
Abstract
Modulation doped metamorphic In0.75Ga0.25As/In0.75Al0.25As quantum wells (QW) were grown on GaAs substrates by molecular beam epitaxy (MBE) with step-graded buffer layers. The electron mobility of the QWs has been improved by varying the MBE growth conditions, including substrate temperature, arsenic over pressure and modulation doping level. By applying a bias voltage to SiO2 insulated gates, the electron density in the QW can be tuned from 1Ã1011 to 5.3Ã1011Â cmâ2. A peak mobility of 4.3Ã105Â cm2Vâ1sâ1 is obtained at 3.7Ã1011Â cmâ2 at 1.5Â K before the onset of second subband population. To understand the evolution of mobility, transport data is fitted to a model that takes into account scattering from background impurities, modulation doping, alloy disorder and interface roughness. According to the fits, scattering from background impurities is dominant while that from alloy disorder becomes more significant at high carrier density.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Chong Chen, Ian Farrer, Stuart N. Holmes, Francois Sfigakis, Marc P. Fletcher, Harvey E. Beere, David A. Ritchie,