Chemical Lattice Imaging Research Articles

Atomic Abruptness and Smoothness at Heterointerfaces: Fact or Fiction?

ABSTRACTIt is now common to claim the fabrication of heterointerfaces, which are atomically flat over distances in the micron range. However, when chemical lattice imaging and digital pattern recognition are combined to examine quantitatively individual semiconductor heterointerfaces of the highest quality, substantial atomic scale roughness is observed. In this paper we review the application of chemical imaging and pattern recogntion techniques to the characterisation of heterointerfaces at near-atomic resolution, and discuss the possible ways the results can be combined with optical measurements to give an overall picture of interfacial roughness.

Local Atomic Interdiffusion in CdTe/HgCdTe Multilayered Structures

ABSTRACTWe combine chemical lattice imaging with digital pattern recognition to study atomic interdiffusion at individual CdTe/HgCdTe interfaces in multi-quantum well structures. In this way we obtain quantitative composition profiles for “as grown” samples, and investigate their development as a function of annealing temperature. Our results indicate that interdiffusion depends on the position of the quantum well with respect to the surface, beginning first at quantum wells close to the surface, and proceeding towards the substrate. Our approach allows the quantification of interdiffusion as a function of time, temperature, and distance from the surface. The implications of these results for the stability of CdTe/HgCdTe structures, and the interpretation of X-ray data are discussed.