Low-temperature scanning tunneling microscopy study of self-assembled InAs quantum dots grown by droplet epitaxy

Corentin Durand , A. Peilloux , K. Suzuki , K. Kanisawa , B. Grandidier , K. Muraki

Using molecular beam epitaxy, we study self-assembled InAs quantum dots (QDs) grown on GaAs (001) substrates by lowtemperature scanning tunneling microscopy. We compare two different growth processes, the well-known Stranski-Krastanow mode and the more recently studied droplet epitaxy mode. We show that, for the same amount of deposited indium, the shape of the dots shows similar anisotropic tendency, but the InAs coverage dependence of the density shows that the growth mechanisms are different at the initial stage of the QD formation. By scanning tunneling spectroscopy at low temperature, we succeed in mapping the local density of states (LDOS) of a single quantum dot grown by the droplet epitaxy. Maps of LDOS are consistent with those previously reported for the Stranski–Krastanow mode; however, energy spectrum of our QDs shows different peak structures

Mots clés: Quantum dots; Droplet epitaxy; Scanning tunneling microscopy; Molecular beam epitaxy; Self-assembled structure; Local density of states; Strained-growth

Domaines: Matière Condensée [cond-mat]

Corentin Durand, A. Peilloux, K. Suzuki, K. Kanisawa, B. Grandidier, et al.. Low-temperature scanning tunneling microscopy study of self-assembled InAs quantum dots grown by droplet epitaxy. Physics Procedia, 2010, Proceedings of the 14th International conference on Narrow Gap Semiconductors and Systems, 3 (2), pp.1299-1304. ⟨10.1016/j.phpro.2010.01.180⟩. ⟨hal-00568565⟩