The authors used depth-resolved cathodoluminescence spectroscopy and current-voltage measurements to probe the temperature-dependent formation of native point defects and reaction layers at metal-ZnO interfaces and their effect on transport properties. These results identify characteristic defect emissions corresponding to metal-Zn alloy versus oxide formation. Au alloys with Zn above its eutectic temperature, while Ta forms oxide blocking layers that reduce current by orders of magnitude at intermediate temperatures. Defects generated at higher temperatures and/or with higher initial defect densities for all interfaces produce Ohmic contacts. These reactions and defect formation with annealing reveal a thermodynamic control of blocking versus Ohmic contacts.
Mosbacker, H. L.,
Hetzer, M. J.,
Look, D. C.,
Song, J. J.,
& Brillson, L. J.
(2007). Thermally Driven Defect Formation and Blocking Layers at Metal-ZnO Interfaces. Applied Physics Letters, 91 (7), 72102.
Copyright © 2007, American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 91.7, and may be found at http://apl.aip.org/resource/1/applab/v91/i7/p072102_s1