Mobility (106 cm2 V-1 s-1) of 2DEGs, 30 nm from ex situ patterned GaAs regrowth interfaces

We have regrown, on ex situ patterned GaAs substrates, using hydrogen radical decontamination, two-dimensional electron gases (2DEGs) confined in 15 nm quantum wells (QWs) with the inverted AlGaAs/GaAs interface 30 nm from the regrowth interface (RI), which conduct before illumination at 1.5 K. Mobilities in excess of 1 x 10(6) cm(2) V-1 s(-1) have been achieved. We have not observed a degradation in the mobility for a constant carrier concentration between 2DEGs, 200 and 30 nm from the RI. A control structure with the 2DEG 30 nm from the RI was also grown on an un-patterned GaAs substrate that was only thermally cleaned, which had a maximum mobility of 3 x 10(4) cm(2) V-1 s(-1) after illumination at 1.5 K. (C) 1998 Elsevier Science S.A. All rights reserved.