Influence of strains at the layer interfaces on the relief of atomically flat cleavages.
In Fig. 1a topography of the cleavage of ZnBeMgSe/GaAs laser heterostructure is presented (cantilever CSC12 was used). In this case the surface is atomically flat, and the topography information is not sufficient to detect all the layers of the laser. There are two meaningful features: a white 2-angstrem-height ridge corresponding to the compressed ZnCdSe quantum well (QW) and 6-angstrem-height step at the interface with GaAs substrate. The ridge corresponding to QW (see a height profile in fig.c) resulted from the compensation of bulk mechanical strains by the surface tension; the step reflects non-ideal structural quality of the first interface. Detailed analysis of the factors responsible for the surface peculiarities on the cleavages of strained heterostructures may be found in .
AFM images are obtained by commercial SPM P4 with CSC12 cantilevers.
On the next pages description of the used lateral force mode and the details of image obtaining are presented. For more information see also paper NN.
Additional information about laser structures were received with usage of Contact EFM, Kelvin mode.