Strain in GaP/GaAs and GaAs/GaP resonant tunnelling heterostructures

In English We studied the morphology of GaP/(001)GaAs and GaAs/(001)GaP heterostructures grown by metal-organic vapour-phase epitaxy and found wire-like surface undulations elongated in the 110 direction. We attribute this elongation to anisotropic lateral growth rates in the 110 and 110 directions, which are due to a different roughness of monolayer surface steps. In III-V materials grown by molecular beam epitaxy. such surface corrugations are usually elongated in 110. We explain this difference by the two growth methods having inverted ratios of lateral growth rates in 110 and 110. Resonant tunnelling diodes fabricated from the GaP/GaAs heterostructures showed very symmetric I-V characteristics. Their peak-to-valley ratio was limited to 2. most probably due to the corrugation of the GaP barriers. (C) 2002 Elsevier Science B.V. All rights reserved.