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HL: Fachverband Halbleiterphysik

HL 3: Heterostructures

HL 3.2: Vortrag

Montag, 23. März 2009, 10:30–10:45, BEY 154

Successful fabrication of h-BN/ZnO heterojunction diodes — •Marc Brötzmann, Hayo Zutz, Anne-Katrin Nix, and Hans Hofsäss — II. Institute of Physics, University of Göttingen

In this work we investigated the electrical properties of h-BN/ZnO-heterostuctures. For this purpose several h-BN-films with thicknesses between 60nm and 80nm were grown on ZnO-substrates using Mass Separated Ion Beam Deposition (MSIBD). The deposition was performed with a substrate-bias of 100eV at room temperature.

The electrical properties were investigated using a two point measurement to record current-voltage (I-U) characteristics in the temperature range of 20-300K. The devices show a distinctive diode characteristic with threshold voltages of 6-8V and breakdown voltages of about 60-80V. We can not verify any satisfying agreement with common conduction mechanisms; therefore an extended conduction model based on the Shockley theory has been developed. In addition we observe huge ideality factors in the range of 75-160 due to high defect density (verified using Transmission Electron Microscopy measurements) and a resulting strong recombination current.

In this presentation we will discuss the development of the conduction model on the basis of temperature dependent I-U characteristics and TEM-measurements. In Addition, first results on photoconductivity behavior are also presented.