Electron mobility engineering in semiconductor heterostructures

It is well known that at low temperatures the acoustic-phonon limited mobility of a two-dimensional electron gas in GaAs heterostructures is determined predominantly by piezoelectric scattering. We suggest a way of significantly enhancing of the acoustic-phonon limited mobility by reducing piezoelectric scattering via inserting thin metal layers at finite distances from the electron channel. As an example, for a GaAs quantum well of View the MathML source width placed between two metal layers and separated from them by View the MathML source, the mobility at View the MathML source increases by about 10 times. Moreover, the mobility increases several times when only one metal layer or highly doped semiconductor is placed near a narrow well.