Atomic-scale structure of self-assembled In(Ga)As quantum rings in GaAs
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 tunnelin...
| Autores: | , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2005 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:dnet:digitalcsic_::a1cc17f61605cea5832a698820ac7351 |
| Acceso en línea: | http://hdl.handle.net/10261/19283 |
| Access Level: | acceso abierto |
| Palabra clave: | Self-assembly Indium compounds Gallium arsenide Semiconductor quantum dots III-V semiconductors Annealing Scanning tunnelling microscopy Atomic force microscopy |
| Sumario: | 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. |
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