Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 87: ZnO: Growth and Defects
HL 87.8: Talk
Friday, March 18, 2011, 12:15–12:30, POT 51
Zn1−xCdxO thin films and heterostructures grown by pulsed laser deposition — •Martin Lange, Christof P. Dietrich, Holger von Wenckstern, Michael Lorenz, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Semiconductor Physics Group, Linnéstr. 5, D-04103 Leipzig, Germany
Effecient optoelectronic devices are based on heterostructures which require band gap engineering. A reduction of the ZnO bandgap is possible when Cd is incorporated.[1] Here, we present an ansatz allowing the incorporation of up to 24 % Cd in ZnO without a phase separation using pulsed laser deposition. Therefore, we applied low substrate temperatures down to room temperature. A red-shift of the near band-edge luminescence down to energies of approximately 2.6 eV was achieved.
We used mixed targets of ZnO and CdO and were therefore able to grow the Zn1−xCdxO directly on the a-plane saphire substrates without surrounding ZnO layers. The thin films exhibit a wurtzite crystal structure with the c-axis parallel to the growth direction. With increasing Cd-content the c-axis constant increases in agreement with literature.[2] The bandgap energy decreases with increasing Cd-content, which was verified by a red-shift of the luminescence maximum and the absorption edge of the Zn1−xCdxO.
Finally, Zn1−xCdxO was combined with ZnO thin films and ZnO nanowires in various heterostructures.
[1] S. Sadofev et al., Appl. Phys. Lett. 89, 201907 (2006)
[2] K. Yamamoto et al., J. Cryst. Growth 312, 1703 (2010)