Infrared transmission spectroscopy of charge carriers in self-assembled InAs quantum dots under surface electric fields

Shovon Pal, Sascha R. Valentin, Nadezhda Kukharchyk, Hanond Nong, Alireza B. Parsa, Gunther Eggeler, Arne Ludwig, Nathan Jukam, Andreas D. Wieck

Published 2014-09-18Version 1

We present a study on the intersublevel spacings of electrons and holes in a single layer of InAs self-assembled quantum dots (SAQDs) using Fourier transform infrared (FTIR) transmission spectroscopy without the application of an external magnetic field. Epitaxial, complementary-doped and semi-transparent electrostatic gates are grown within the ultra high vacuum conditions of molecular beam epitaxy to voltage-tune the device, while a two dimensional electron gas (2DEG) serves as back contact. Spacings of the hole sublevels are indirectly calculated using the photoluminescence spectroscopy along with FTIR spectroscopy. The observed spacings fit well to the calculated values for both electrons and holes. Additionally, the intersubband resonances of the 2DEG are enhanced due to the QD layer on top of the device.