Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 36: ZnO: preparation and characterization II

HL 36.6: Vortrag

Mittwoch, 25. März 2009, 15:30–15:45, POT 51

Deep levels in nitrogen implanted ZnO — •Matthias Schmidt¹, Martin Ellguth¹, Florian Schmidt¹, Thomas Lüder¹, Rainer Pickenhain¹, Marius Grundmann¹, Gerhard Brauer², and Wolfgang Skorupa² — ¹Universität Leipzig, Institut für Experimentelle Physik II, 04103 Leipzig, Germany — ²Forschungszentrum Dresden – Rossendorf e.V., Dresden, Germany

We investigated deep levels in a nitrogen implanted, PLD grown ZnO thin film. Subsequent to the ion implantation the sample has been thermally annealed. In preparation of capacitance spectroscopy measurements a Schottky contact made from evaporated palladium was deposited on the sample. From capacitance – voltage measurements the spacial dependence of the net doping concentration was obtained. Deep level transient spectroscopy was employed for the characterisation of deep levels with binding energies E_c − E_d < 700 meV below the conduction band edge. The prominent deep level E3 and a deeper one with E_c − E_d≈ 590 meV were detected. The presence of further defects was proven by photo – capacitance and photo – current measurements. A strong increase of the capacitance as well as on the current was observed for excitation with energies approx. 200 meV below the bandgap. This behaviour hints to the existence of a trap close to the valence band edge.