[Zurück]

N. Le Biavan, M. Hugues, B. Meng, M. Montes Bajo, J. Tamayo-Arriola, A. Jollivet, B. Hinkov, H.T. Hoang, A. Torres-Pardo, D. Lefebvre, Y. Cordier, B. Vinter, M. Tchernycheva, F.H. Julien, G. Strasser, A. Hierro, J. Faist, J. Chauveau:
"Electronic coupling in ZnO asymmetric quantum wells for intersubband cascade devices";
Vortrag: SPIE Photonics West 2020, San Francisco; 01.02.2020 - 06.02.2020; in: "Proceedings Volume 11281, Oxide-based Materials and Devices XI", (2020), Paper-Nr. 11281-58, 1 S.

Recently Zinc Oxide has received a renewed attention for the realization of intersubband devices such as quantum cascade lasers (QCLs). Indeed this material is predicted to be able to tackle the main limitation of current terahertz (THz) QCLs: the limited operation temperature. We report the observation of electronic coupling within ZnO/(Zn, Mg)O asymmetric quantum wells (QWs), first step towards this goal. Samples were grown by molecular beam epitaxy (MBE) with surfaces down to 0.4 nm. X-ray reflectivity (XRR) was used for thickness measurements checking and for the investigation of the interface quality. Atomic resolution scanning transmission electron microscopy (STEM) images reveals that we are able to grow 2 monolayers (MLs) thin (Zn, Mg)O barriers in a reproducible way while keeping abrupt interfaces. Room temperature (RT) photoluminescence (PL) spectra show that QWs are still coupled when separated by a 1.0 nm thick barrier. On the contrary, a 4.0 nm thick barrier allows no coupling. Doped samples were investigated by absorption experiment. Absorption spectra were successfully fitted by a theoretical model, proving a clear electronic coupling in our heterostructures. This demonstration allows us to seriously envision the realization of ZnO based intersubband devices.

http://dx.doi.org/10.1117/12.2547478

https://publik.tuwien.ac.at/files/publik_288466.pdf