This article is cited in 1 paper

Semiconductor structures, low-dimensional systems, quantum phenomena

Excitonic spectrum of the ZnO/ZnMgO quantum wells

M. A. Bobrov^a, A. A. Toropov^a, S. V. Ivanov^a, A. El-Shaer^b, A. Bakin^b, A. Waag<sup>b

a</sup> Ioffe Institute, St. Petersburg
^b Institute of Semiconductor Technology, TU Braunshweig, D-38106 Braunschweig, Germany

Abstract: Excitonic spectrum of the wurtzite ZnO/Zn$_{1-x}$Mg$_x$O quantum wells with a width on the order of or larger than the Bohr radius of the exciton has been studied; the quantum wells have been grown by the method of molecular beam epitaxy (with plasma-assisted activation of oxygen) on substrates of sapphire (0001). Low-temperature (25 K) spectra of photoluminescence excitation (PLE) have been experimentally measured, making it possible to resolve the peaks of exciton absorption in the quantum well. The spectrum of excitons in the quantum well is theoretically determined as a result of numerical solution of the Schrödinger equation by the variational method. The value of elastic stresses in the structure (used in calculations) has been determined from theoretical simulation of measured spectra of optical reflection. A comparison of experimental data with the results of calculations makes it possible to relate the observed features in the PLE spectra to excitons, including the lower level of dimensional quantization for electrons and two first levels of holes for the $A$ and $B$ valence bands of the wurtzite crystal. The values of the electron and hole masses in ZnO are refined, and the value of the built-in electric field introduced by spontaneous and piezoelectric polarizations is estimated.

Received: 30.11.2010
Accepted: 06.12.2010

 English version: Semiconductors, 2011, 45:6, 766–770

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