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Atomic structure and optical properties of InAs submonolayer depositions in GaAs

: Lenz, A.; Eisele, H.; Becker, J.; Schulze, J.-H.; Germann, T.D.; Luckert, F.; Pötschke, K.; Lenz, E.; Ivanova, L.; Strittmatter, A.; Bimberg, D.; Pohl, U.W.; Dähne, M.


Journal of vacuum science and technology B. Microelectronics and nanometer structures 29 (2011), Nr.4, Art. 04D104, 8 S.
ISSN: 0734-211X
ISSN: 1071-1023
ISSN: 2166-2746
ISSN: 2166-2754
Fraunhofer HHI ()

Using cross-sectional scanning tunneling microscopy and photoluminescence spectroscopy, the atomic structure and optical properties of submonolayer depositions of InAs in GaAs are studied. The submonolayer depositions are formed by a cycled deposition of 0.5 monolayers InAs with GaAs spacer layers of different thicknesses between 1.5 and 32 monolayers. The microscopy images exhibit InAs-rich agglomerations with widths around 5 nm and heights of up to 8 monolayers. A lateral agglomeration density in the 1012cm -2 range is found. During the capping of the InAs depositions a vertical segregation occurs, for which a segregation coefficient of 0.73 was determined. In the case of thin GaAs spacer layers, the observed segregation forms vertically connected agglomerations. The photoluminescence spectra exhibit peaks with linewidths below 10 meV and show a considerable dependence of the peak energy on the spacer thickness, even up to 32 monolayers GaAs, indicating a long range e lectronic coupling.