Low temperature sputter-deposited ZnO films with enhanced Hall mobility using excimer laser post-processing

Tsakonas, C. ORCID: 0000-0002-7342-3405, Kuznetsov, V.L., Cranton, W.M., Kalfagiannis, N. ORCID: 0000-0002-4030-5525, Abusabee, K.M., Koutsogeorgis, D.C. ORCID: 0000-0001-6167-1084, Abeywickrama, N. and Edwards, P.P., 2017. Low temperature sputter-deposited ZnO films with enhanced Hall mobility using excimer laser post-processing. Journal of Physics D: Applied Physics, 50 (48), p. 485306. ISSN 0022-3727

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Abstract

We report the low temperature (T<70 ºC) fabrication of ZnO thin films (~140 nm) with Hall mobility of up to 17.3 cm2 V-1 s-1 making them suitable for thin film transistor (TFT) applications. The films were deposited by rf magnetron sputtering at T<70 ºC and subsequently laser processed in ambient temperature in order to modify the Hall mobility and carrier concentration. Medium-to-low energy laser radiation densities and a high number of pulses were used to avoid damaging the films. Laser annealing of the films after aging in the lab under 25% - 35% relative humidity and at an average illuminance of 120 lux resulted in an overall higher mobility and relatively low carrier concentration in comparison to the non-aged films that were laser processed immediately after deposition. A maximum overall measured Hall mobility of 17.3 cm2 V-1s-1 at a carrier density of 2.3×1018 cm-3 was measured from a 1 GΩ as deposited and aged film after the laser treatment. We suggest that the aging of non-processed films reduces structural defects mainly at grain boundaries by air species chemisorption, with concomitant increase in thermal conductivity so that laser processing can have an enhancing effect. Such a processing combination can act synergistically and produce suitable active layers for TFT applications with low temperature processing requirements.

Item Type: Journal article
Publication Title: Journal of Physics D: Applied Physics
Creators: Tsakonas, C., Kuznetsov, V.L., Cranton, W.M., Kalfagiannis, N., Abusabee, K.M., Koutsogeorgis, D.C., Abeywickrama, N. and Edwards, P.P.
Publisher: IOP Publishing Ltd.
Date: 6 December 2017
Volume: 50
Number: 48
ISSN: 0022-3727
Identifiers:
NumberType
10.1088/1361-6463/aa9316DOI
Divisions: Schools > School of Science and Technology
Depositing User: Jill Tomkinson
Date Added: 04 Jan 2018 12:01
Last Modified: 04 Jan 2018 12:01
URI: http://irep.ntu.ac.uk/id/eprint/32279

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