Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 12: Poster I

HL 12.61: Poster

Montag, 8. März 2004, 16:30–19:00, Poster A

Capacitance-voltage (CV) measurements on a InAs quantum dot ensemble and on single InAs quantum dots embedded in a GaAs matrix — •Heidemarie Schmidt¹, Stefan Jaensch¹, Gerald Wagner², and Marius Grundmann¹ — ¹Universität Leipzig, Fakultät für Physik und Geowissenschaften — ²Institut für Nichtklassische Chemie an der Universität Leipzig

Using Stranski-Krastanov growth mode, self-assembled InAs quantum dots (QD) have been incorporated at 485 ^∘C in n-type GaAs grown by MBE on (100)-GaAs n⁺-substrates. A typical dot diameter of 11.4 ± 2 nm and a dot density of 8×10¹⁰ cm⁻² with a mean dot distance of ca. 40 nm was deduced from transmission electron microscopy. The InAs wetting layer thickness amounts to one monolayer. Temperature dependent CV measurements using Au-Schottky contacts with an area of 10⁻³ cm² that cover an ensemble of 10⁸ QD, show a plateau in the bias region from -2 V to -5 V. That CV plateau is due to charge carrier accumulation at the position of the QD and wetting layer. Scanning capacitance microscopy (SCM) allows for CV measurements at room temperature on the 25-50 nm conductive tip diameter scale, and will be compared to the CV experiments on large ensembles.