Fermi Level Pinning at GaN-Interfaces: Correlation of Electrical Admittance and Transient Spectroscopy


Hartmut P. Witte, Andre Andre, Marko Lisker, Dirk Rudloff, Juergen Christen, Alois Krost
Otto-von-Guericke-University Magdeburg

Martin Stutzmann
Technical University Munich

F. Scholz
University Stuttgart

This article was presented as part of Symposium W, "Gallium Nitride and Related Alloys" at the 1999 Fall Meeting of the Materials Research Society held in Boston, Massachusetts, November 28-December 3

Abstract

In GaN layers grown by molecular beam epitaxy as well as metal organic vapor phase epitaxy significant differences were found in the appearance of deep defects de-tected by thermal admittance spectroscopy as compared for deep level transient spectros-copy measurements. While, thermal admittance spectroscopy measurements which were made under zero bias conditions only show thermal emissions at activation energies be-tween 130 and 170 meV, further deep levels existing in these GaN layers were evidenced by transient spectrocopy. This discrepancy is explained by a pinning effect of the Fermi level at the metal / GaN interface induced by high a concentration of the deep levels showing up in thermal admittance spectroscopy. We compare our results with a GaAs:Te Schottky- diode as a refernec sample. Here, both spectroscopic methods give exactly the same deep level emissions.

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Cite this article as: MRS Internet J. Nitride Semicond. Res. 5S1, W11.82 (2000).


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MRS Internet Journal of Nitride Semiconductor Research
last updated Wednesday, May 17, 2000 5:02:44 PM.
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