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HL: Fachverband Halbleiterphysik

HL 37: Oxide Semiconductors

HL 37.5: Talk

Thursday, March 15, 2018, 10:30–10:45, EW 203

Tunable intersubband transitions in ZnO/ZnMgO multiple quantum wells in the mid infrared spectral range — •Laura Orphal, Sascha Kalusniak, Oliver Benson, and Sergey Sadofev — Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany

ZnO is considered as a promising material for mid IR intersubband devices, and possibly also for the THz regime [1]. We demonstrate the ability to control intersubband transition (ISBT) energies in O-polar ZnO/Zn_0.60Mg_0.40O multiple quantum well structures grown by molecular beam epitaxy on sapphire [2]. The ISBT between the first and the second electronic energy state within the conduction band are observed by infrared spectroscopy at room temperature. Absorption features due to the ISBT occur only for light polarized normal to the quantum well plane (p-polarized) according to the polarization selection rules. By variation of the quantum well width the ISBT energies can be tuned from 290 to 370 meV. The experimental results are in good agreement with theoretical calculations assuming the presence of internal electric fields of 2 MV/cm.

[1] E. Bellotti, K. Driscoll, T. D. Moustakas, and R. Paiella, Journal of Applied Physics 105, 113103 (2009).

[2] L. Orphal, S. Kalusniak, O. Benson, S. Sadofev, AIP Advances 7, 115309 (2017).