1. Composition distribution and electrical properties of
individual GeSi quantum rings
Y. Lv, Y. F. Zhang, S. H. Zhao, J. Cui, Z. M. Jiang and X. J. Yang
Surface Physics Laboratory, Fudan University, Shanghai , China
The composition distribution of individual self-assembled GeSi quantum rings (QRs) was studied by atomic force microscopy combined with selective wet chemical etching procedures. By using the in situ imaging method, the composition distributions of the same specifically QRs after different etching processes were obtained. Therefore the whole composition profiles of several specifically QRs were revealed. After each etching process, the electrical properties of the individual QRs were investigated by conductive atomic force microscopy (CAFM). The correlation between the electrical properties of GeSi QRs and its composition distribution was discussed.
CAFM schematic diagram R1 R1 R2 R2
Topographic images of QRs after different etching processes (left) and the representative profiles of two individual QRs (right).
Sample structure and its 3D topography
Schematic map of the composition distribution of GeSi QR.
(a)
(b)
(c)
(d)
(e)
(f)
Current images of GeSi QRs (a) as grown; (b) after etching in HF solution for 30s; after etching in NHH solution for (c) 10s, (d) 1min, (e) 10min; and (f) after etching in BPA solution for 90s. All images were obtained at a sample bias voltage of -1V.
Summary
The composition distribution of GeSi quantum rings was obtained by atomic force microscopy combined with selective wet chemical etching.
The electrical properties of individual QRs are not determined by its composition distribution.