Composition and strain in SiGe/Si(001) “nanorings” revealed by combined x-ray and selective wet chemical etching methods

Abstract

The authors used x-ray diffraction to investigate strain and composition in SiGe nanorings formed during partial Si capping of self-assembled SiGe/Si(001) islands. The obtained results are corroborated with selective wet chemical etching experiments. Clear evidence is provided that rings are composed of a Ge rich core surrounded by Si richer ridges indicating that a substantial material redistribution occurs during the shape transformation from SiGe islands to rings. The results suggest that SiGe ring formation is driven by strain relief.

Compositional mapping of semiconductor quantum dots and rings

“…The dot-to-ring evolution as a function of capping in the SiGe material system was studied with anomalous grazing incidence XRD by Stoffel et al [123], with similar results as what was found in Ref. [95] (see Section 3.1.5).…”

“…The same technique has been applied to the study of Ge/Si islands overgrown with Si [123,151,152]. If the proper growth protocol is employed, this leads to the formation of quantum rings.…”

Nanoscale electrical property studies of individual GeSi quantum rings by conductive scanning probe microscopy

“…However, compared to the intensive theoretical studies on the ideal or lithographed QRs, the studies addressing the self-assembled QRs are relatively lacked. Furthermore, among the existing studies on self-assembled QRs, most of them are dealing with the growth mechanisms or electronic properties of QRs [6-11], while some of the studies are performed on the QRs' composition and strain distributions or atomic structures [12-16]. The electrical characteristics of the QRs, which are of vital importance to nano-electronic applications, have much less been concerned.…”

Self-assembled formation and transformation of In/CdZnTe(110) nano-rings into camel-humps

“…In addition, elasticity and, in particular, shear modulus have also been shown to affect the QD-to-NR transformation. 28 Nano-ring formation in other compound 7 and group IV 16,29 semiconductors have been less explored. Even smaller body of work on direct fabrication of III-V NRs (e.g., InAs/InP, 19,27 GaSb/GaAs (Ref.…”