High-resolution analytical transmission electron microscopy of semiconductor quantum structures

Abstract

Analytical transmission electron microscopy was applied to characterize the size, shape, real structure, and, in particular, the composition of different semiconductor quantum structures. Its potential applicability is demonstrated for heterostructures of III-V semiconducting materials and II-VI ones, viz. (In,Ga)As quantum wires on InP and (In,Ga)As quantum dots on GaAs both grown by metal organic chemical vapor deposition, and CdSe quantum dots on ZnSe grown by molecular beam epitaxy. The investigations carried out show that the element distribution even of some atomic layers can be detected by energy-dispersive X-ray spectroscopy, however, exhibiting a smeared profile. Contrary to that, sub-nanometre resolution has been achieved by using energy-filtered transmission electron microscopy to image quantum dot structures.