Interplay between quantum well width and interface roughness for electron transport mobility in GaAs quantum wells

We report transportmobility measurements for clean, two-dimensional (2D) electron systems confined to GaAsquantum wells(QWs),grown viamolecular beam epitaxy, in two families of structures, a standard, symmetrically doped GaAs set ofQWs with Al0.32Ga0.68As barriers and one with additional AlAscladding surrounding theQWs. Our results indicate that themobility in narrowQWs with nocladding is consistent with existing theoretical calculations whereinterface roughness effects are softened by the penetration of the electronwave function into the adjacent low barriers. In contrast, data from AlAs-clad wells show a number of samples where the 2Delectron mobility is severely limited byinterface roughness. These measurements across three orders of magnitude inmobility provide a road map of reachablemobilities in thegrowth of GaAs structures of differentelectron densities, well widths, and barrier heights.

Source: Applied Physics Letters - December 6, 2016 Category: Physics Authors: D. Kamburov, K. W. Baldwin, K. W. West, M. Shayegan and L. N. Pfeiffer Source Type: research