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HL: Halbleiterphysik

HL 35: Symposium Ferromagnetische Halbleiter

HL 35.3: Vortrag

Donnerstag, 11. März 2004, 11:15–11:45, H15

ZnO-MOVPE: Present State and Prospective Applications in Optoelectronics and Magnetoelectronics — •Andreas Waag — Institut für Halbleitertechnik, TU Braunschweig

Due to its band gap of 3.3 eV and exciton binding energy of 60 meV, ZnO is a very interesting candidate for UV optoelectronics. Beyond that, the incorporation of magnetic impurities allows to fabricate semimagnetic semiconductors, which are transparent and ferromagnetic at room temperature. The combination with n-type doping makes magnetic ZnO very interesting for spinelectronics. Here, we give an overview on our activities concerning the MOVPE growth of ZnO-related thins films and heterostructures. After a thourough optimisation of the growth process, ZnMgO-ZnO quantum well structures could be fabricated, indicating a good optical quality. The incorporation of Cd, however, suffers from phase separation, and two distinctly different Cd concentrations have been detected in ZnCdO films. In addition, the self-organised growth of ZnO nanorods could be demonstrated by a suitable choice of MOVPE growth parameters. Nanorods of 30 nm diameter and a height of up to 5 µ m could be achieved. The optical quality of these nanorods is very good, indicating that open lying surfaces play a minor role in terms of non-radiative recombination. The incorporation of magnetic ions has been achieved, both into normal layers as well as nanrods, and ferromagnetic behaviour has been detected.