MBE growth of AlGaAs GaAs heterostructure and silicon doping on GaAs(n 1 1)A (n=1-4) substrates

Undoped AlGaAs/GaAs asymmetric double quantum wells (ADQWs) and Si-doped si ngle epitaxial GaAs layers were prepared on non-(1 0 0) oriented GaAs(n 1 1 )A (n = 1-4) substrates in molecular beam epitaxy (MBE) at different As pre ssures. The grown thickness was the same for (1 0 0) and (n 1 1)A substrate s as revealed by a transmission electron microscope observation. The surfac es of(n 1 1)A samples change from rough to smooth and featureless with incr easing As pressure, while that of(1 0 0) sample shows an inverse change acc ording to the atomic force microscopy results. Photoluminescence spectra of ADQWs have shown that, the luminescence peak energies shift towards lower energy direction with increasing As pressures. The conduction type of (n 1 1)A was p-type for lower As pressure and n-type for higher As pressure. (C) 1999 Elsevier Science B.V. All rights reserved.