Superior molecular beam epitaxy (MBE) growth on (N 1 1)A GaAs

The (3 1 1)A and (5 1 1)A planes of GaAs were used for the growth of high-quality two-dimensional hole gas (2DHG) and electron gas (2DEG) structures, respectively. A back-gated, inverted interface, AlGaAs/GaAs structure in which a 2DHG or a 2DEG was embedded was studied. This particular structure enabled the two-dimensional carrier concentration to be varied over two orders of magnitude in a single device, as well as the measurement of extremely low carrier densities in the mid 109 cm~2 range. The remarkably low carrier concentration we were able to achieve in both a 2DHG and a 2DEG opens new frontiers for the study of mesoscopic phenomena governed by Coulomb interactions between carriers, in particular, the possible existence of a Wigner crystal. ( 1999 Elsevier Science B.V. All rights reserved. PACS: 81.15.Hi; 81.05.Ea; 73.40.Ty