Low temperature growth of highly doped GaAs:Si by atomic layer molecular beam epitaxy

Abstract

Two-dimensional growth kinetics characteristic of atomic layer molecular beam epitaxy (ALMBE) allows to extend the range of GaAs growth conditions to low temperatures while preserving excellent crystallinity and layer morphology. In this work we have used ALMBE technique to obtain GaAs layers highly doped with silicon at substrate temperatures from 200 to 400°C. At these low growth temperatures donor incorporation is excellent and electron densities of 2×1019 cm-3 were reached, limited by the pinning of Fermi level at the DX level. Samples exhibit persistent photoconductivity due to the existence of a DX level resonant with the conduction band.