Effects of high temperature annealing on single crystal ZnO and ZnO devices
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Date
Authors
Mtangi, Wilbert
Auret, Francois Danie
Diale, M. (Mmantsae Moche)
Meyer, Walter Ernst
Chwanda, Albert
De Meyer, Hannes
Janse van Rensburg, Pieter Johan
Nel, Jacqueline Margot
Journal Title
Journal ISSN
Volume Title
Publisher
American Institute of Physics
Abstract
We have systematically investigated the effects of high-temperature annealing on ZnO and ZnO
devices using current voltage, deep level transient spectroscopy (DLTS) and Laplace DLTS
measurements. Current–voltage measurements reveal the decrease in the quality of devices fabricated
on the annealed samples, with the high-temperature annealed samples yielding devices with low
barrier heights and high reverse currents. DLTS results indicate the presence of three prominent
defects in the as-received samples. Annealing the ZnO samples at 300 C, 500 C, and 600 C in Ar
results in an increase in reverse leakage current of the Schottky contacts and an introduction of a new
broad peak. After 700 C annealing, the broad peak is no longer present, but a new defect with an
activation enthalpy of 0.18 eV is observed. Further annealing of the samples in oxygen after Ar
annealing causes an increase in intensity of the broad peak. High-resolution Laplace DLTS has been
successfully employed to resolve the closely spaced energy levels.
Description
Keywords
High-temperature annealing, Single crystal ZnO, ZnO devices, Laplace DLTS, Current voltage
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Citation
Mtangi, W, Auret, FD, Diale, M, Meyer, WE & Chawanda, A 2012, 'Effects of high temperature annealing on single crystal ZnO and ZnO devices', Journal of Applied Physics, vol. 111, no. 8, pp. 084503-1-084503-6.