Peak electron mobilities between 2.75 and 3.32×105 cm2 V−1 s−1 in GaAs grown by molecular beam epitaxy with As2

Exceptionally pure n-GaAs has been grown without intentional doping by solid-source molecular beam epitaxy (MBE) using arsenic dimers (As2). Peak electron mobilities in the range 2.75–3.32×105 cm2 V−1 s−1 at temperatures of ≊40–50 K with free-electron densities n=1×1014 cm−3 have been measured for a series of layers grown under a variety of conditions. These mobilities are among the highest recorded for MBE-grown GaAs.