2024-03-29T08:43:44Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/319752017-02-27T16:48:22Zcom_10261_36com_10261_4col_10261_289
Atomic-scale structure and formation of self-assembled In(Ga)As quantum rings
Offermans, P.
Koenraad, P. M.
Wolter, J. H.
Granados, Daniel
García Martínez, Jorge Manuel
Fomin, Vladimir M.
Gladilin, V. N.
Devreese, J. T.
Quantum ring
Quantum dot
Cross sections
STM
5 páginas, 5 figuras.-- PACS: 68.37.Ef; 68.65.Hb; 81.07.Ta.-- Proceedings of the 12th International Conference on Modulated Semiconductor Structures.
We present an atomic-scale analysis of the indium distribution of self-assembled (In,Ga)As quantum rings (QRs), which are formed from InAs quantum dots by capping with a thin layer of GaAs and subsequent annealing. We find that the size and shape of QRs as observed by cross-sectional scanning tunneling microscopy (X-STM) deviate substantially from the ring-shaped islands as observed by atomic force microscopy on the surface of uncapped QR structures. We show unambiguously that X-STM images the remaining quantum dot material whereas the AFM images the erupted quantum dot material. The remaining dot material shows an asymmetric indium-rich crater-like shape with a depression rather than an opening at the center and is responsible for the observed electronic properties of QR structures. These quantum craters have an indium concentration of about 55% and a diameter of about 20 nm, which is consistent with the observed electronic radius of QR structures. Based on the structural information from the X-STM measurements, we calculate the magnetization as a function of the applied magnetic field. We conclude that, although the real QR shape differs strongly from an idealized circular-symmetric open ring structure, Aharonov–Bohm-type oscillations in the magnetization can be expected.
This work was partially supported by the GOA BOF UA
2000, IUAP, FWO-V projects G.0274.01N, G.0435.03, the
WOG WO.025.99N (Belgium), the EC Network of
Excellence SANDiE, Contract no. NMP4-CT-2004-
500101 and the EC GROWTH Programme, NANOMAT
project G5RD-CT-2001-00545 and NANOSELF project
TIC2002-04096-C03-03.
Peer reviewed
2011-02-03T13:52:02Z
2011-02-03T13:52:02Z
2006-05
artículo
http://purl.org/coar/resource_type/c_6501
Physica E 32(1-2): 41-45 (2006)
1386-9477
http://hdl.handle.net/10261/31975
10.1016/j.physe.2005.12.005
en
http://dx.doi.org/10.1016/j.physe.2005.12.005
none
Elsevier