| AVS 54th International Symposium | |
| Nanometer-scale Science and Technology | Thursday Sessions |
| Session NS-ThP |
| Session: | Nanometer-Scale Science & Techology Poster Session II |
| Presenter: | B. Vlahovic, North Carolina Central University |
| Authors: | I. Filikhin, North Carolina Central University M.H. Wu, North Carolina Central University V.M. Suslov, North Carolina Central University B. Vlahovic, North Carolina Central University |
| Correspondent: | Click to Email |
We model an InGaAs/GaAs quantum dot (QD),including the height dependence of the Ga content of the QD. The effect of material mixing on the electron energy spectra is considered, using the experimentally measured height dependence of the Ga fraction from Ref.1 Our theoretical model is based on a single sub-band approach with an energy dependent effective electron mass. We apply an approach in which the combined effect of strains, piezoelectricity and interband interactions are simulated by an effective potential2. It is shown that these effects may be taken into account in an effective manner using this approach. Based on our model, we perform an analysis of the results obtained by direct treatment of strain effects in Refs.3 ("ab initio" calculations). To prove the adequacy of our model, we compare the results obtained for energy spectra of few electrons tunnelling into InAs/GaAs QDs, with experimental capacitance-gate-voltage data4. We find that the effective method is valid for the case of material mixing in the InGaAs/GaAs quantum dot. In the case of a linear height dependence of the Ga fraction, the strength of the effective potential must be chosen to correspond with the averaged value for the Ga distribution function. Effects of the QD cross section and the Ga fraction distribution are studied. We also compare our results with those obtained from psuedopotential calculations5.
This work was partly supported by the Department of Defense and NASA through Grants, W911NF-05-1-0502 and NAG3-804, respectively.
1 I. Kegel, T. H. Metzger, A. Lorke, J. Peisl, J. Stangl, G. Bauer, J. M. García, P. M. Petroff, Phys. Rev. Lett. 85, 1694, (2000).
2 I. Filikhin, V. M. Suslov and B. Vlahovic, Phys. Rev. B 73, 205332 (2006).
3 M. Grundmann, et al., Phys. Rev. B 52, 11969,(1995); O. Stier, et al. Phys. Rev. B 59, 5688,(1999).
4 B. T. Miller, et al. Phys. Rev. B 56, 6764 (1997); R.J. Warburton, et al. Phys. Rev. B 58, 16221 (1998); A. Lorke, et al. Phys. Rev. Lett. 84, 2223 (2000).
5 G. Bester, A. Zunger,X. Wu, D. Vanderbilt, Phys. Rev. B 74, 081305R (2006).