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HL: Halbleiterphysik

HL 3: Spintronik I

HL 3.5: Vortrag

Freitag, 4. März 2005, 11:45–12:00, TU P164

First-principles studies of Mg_xZn_1−xO alloys — •J. Henk¹, M. Bouhassoune¹, A. Ernst¹, P. Bruno¹, M. Däne², D. Ködderitzsch², and W. Hergert² — ¹MPI für Mikrostrukturphysik, Halle/S., Germany — ²Martin-Luther-Universität Halle-Wittenberg, Halle/S., Germany

Recent research on O-based semiconductors (e. g., ZnO, MgO) suggested an enormous potential for applications in optics and electronics. One important parameter in device design is the width of the fundamental bandgap which, for example, determines the conductance of tunneling devices. One method to modify the band gap is alloying (‘bandgap engineering’). We report on a first-principles study of Mg_xZn_1−xO for various concentrations x and crystal structures. The phase transition from the wurtzite (ZnO) to the rock-salt structure (MgO) was found at x = 0.36, i. e., close to the experimental value of x_exp = 0.4. The fundamental band gap increases upon alloying of ZnO with Mg. Although its size is underestimated due to the local-density approximation, the trends in experiment are fully reproduced.