STRAIN TRANSFER BETWEEN GAAS GAINAS STRAINED LAYERS

Cleaved wedge samples have been used to assess the strain distribution in several strained layer superlattices grown by MBE. The materials system is GaAs/Ga(1-x)In(x)As with x = 0.2. A series of wells of increasing thickness has been studied; the strain in the well and the extent of the strain transfer to the barrier material between the wells have been assessed from the curvature of thickness fringes. The extent to which this contrast results from relaxation at the wedge corner is discussed. A finite element programme has been used to calculate displacement and strain distributions in the structure and a comparison is made with the TEM observations.