Paper EM+NC-ThM4
Photoluminescece Spectroscopy on Near Surface InAs Quantum Dots and Wetting Layers

Thursday, October 23, 2008, 9:00 am, Room 210

The electronic and optical properties of self-assembled (SA) InAs quantum dots (QDs) prepared by MBE or MOCVD have been one of the key topics of quantum nanostructures during the past few decades. In contrast to colloidal quantum dots such as CdSe with tri-octylphosphine oxide where the ligands plays a major role in passivating the surface,¹ SA InAs QDs are usually investigated without much concern on their surface/interface properties. However, we have shown that capping on the InAs QDs strongly influence their photoluminescence (PL)² or that the conductivity of surface InAs QDs strongly depends on their size.³ More recently, it has been shown that surface and near surface InAs QDs exhibit features different from those of the well-buried.⁴ Here, we have performed PL and PL excitation (PLE) spectroscopies on near surface InAs QDs and wetting layer (WL) to further investigate the influence of surface and interfaces of such structures. While we observed PL features similar to those reported in ref. 4, we have also found those that are different. PL and PLE measurements reveal that the carrier dynamics are stongly influenced by the surfaces and interface structures of the QDs and WL. We will discuss the mechanisms that could be governing such observations.

¹ C. B. Murray, D. J. Norris, and M. G. Bawendi, J. Am. Chem. Soc. 115, 8706 (1993).
² I. Kamiya, I. Tanaka, and H. Sakaki, Physica E2, 637 (1998).
³ I. Tanaka, I. Kamiya, H. Sakaki, N. Qureshi, S. J. Allen, and P. M. Petroff, Appl. Phys. Lett. 74, 844 (1999).
⁴ B. L. Liang, Zh. M. Wang, Y. I. Mazur, G. J. Salamo, E. A. DeCuir, and M. O. Manasreh, Appl. Phys. Lett. 89, 043125 (2006).