Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 32: Poster I: Group II - Oxides

HL 32.21: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D1

Laplace-transform deep-level transient spectroscopy in ZnO thin films — •Florian Schmidt, Holger von Wenckstern, Matthias Schmidt, Martin Ellguth, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Abteilung Halbleiterphysik, Linnéstraße 5, 04103 Leipzig

Deep-level transient spectroscopy (DLTS) is a space charge spectroscopic method commonly used for the characterization of semiconducting materials. The time constant resolution of standard DLTS using boxcar or lock-in techniques is however too poor for studying fine structure in emission processes. Digital transient processing, e.g. used in Laplace-transform deep-level transient spectroscopy (LDLTS), enables more sensitive deconvolution of capacitance transients.

We investigated ZnO thin films grown by pulsed-laser deposition by using LDLTS and demonstrated, that DLTS is not suited to characterize the two closely lying levels E3/E3’ [1] appropriately. Instead, LDLTS is necessary to determine defect parameters as thermal activation energy E_t and apparent capture cross-section σ unambiguously. We found for E3 E_t = 295   meV and σ = 4 × 10⁻¹⁶   cm² and for E3’ E_t = 386   meV and σ = 4 × 10⁻¹⁴   cm².

[1] F.D. Auret et al., Physica B 401-402 (2007) 378