(click for full image)
(a). The screening effect on a gaussian potential of width 100 Å in one of the quantum wells. The dotted curve is the bare potential. The dash-dotted, dashed, full and dash-triple-dotted curves are for the carrier concentrations 2x1017 cm-3, 4x1017 cm-3, 2x1018 cm-3 and 1x1019 cm-3, respectively. All curves have been scaled to the value at the center of the unscreened potential. We have plotted the potentials with reverted sign to get the impression of a potential well. The screened potentials have Friedel oscillations at large separations. (b). The well depths of screened gaussian potentials for different carrier concentrations, indicated in the figure, as functions of potential width.
© 1999-2004 The Materials Research Society
