Localized defect states and charge trapping in Al₂O₃ films prepared by atomic layer deposition

  • The evaluation of the electronic structure and intrinsic defect mechanisms in Al₂O₃ thin films is essential for their effective use in applications with desired functionality such as surface passivation schemes for solar cells [1]. We present a comparative study of different Al₂O₃ films grown by atomic layer deposition (ALD) [2]. The layers were deposited on different substrates using the same aluminum precursor (TMA, trimethylalumium) and employing different process parameters (thermal-ALD, plasma-enhanced-ALD, substrate temperature). These films were characterized by resonant photoelectron spectroscopy and by electrical measurements (capacitance-voltage). For all films investigated intrinsic defect states within the electronic band gap were observed including excitonic, polaronic, and charge-transfer defect states, where their relative abundance is subject of the choice of ALD parameters and of the used substrate. The spectroscopic assigned in-gap defect states are related with electronic charges as determined in the electricalThe evaluation of the electronic structure and intrinsic defect mechanisms in Al₂O₃ thin films is essential for their effective use in applications with desired functionality such as surface passivation schemes for solar cells [1]. We present a comparative study of different Al₂O₃ films grown by atomic layer deposition (ALD) [2]. The layers were deposited on different substrates using the same aluminum precursor (TMA, trimethylalumium) and employing different process parameters (thermal-ALD, plasma-enhanced-ALD, substrate temperature). These films were characterized by resonant photoelectron spectroscopy and by electrical measurements (capacitance-voltage). For all films investigated intrinsic defect states within the electronic band gap were observed including excitonic, polaronic, and charge-transfer defect states, where their relative abundance is subject of the choice of ALD parameters and of the used substrate. The spectroscopic assigned in-gap defect states are related with electronic charges as determined in the electrical measurements. [1] G. Dingemans and W.M.M. Kessels, J. Vac. Sci. Technol. A 30, 040802 (2012). [2] K. Henkel, M. Kot, D. Schmeißer, J. Vac. Sci. Technol. A 35, (2017), accepted.show moreshow less

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Metadaten
Author: Karsten HenkelORCiDGND, Małgorzata KotORCiD, Dieter SchmeißerORCiD
URL:http://www.dpg-verhandlungen.de/year/2017/conference/dresden/part/ds/session/32/contribution/4
ISSN:0420-0195
Title of the source (German):Verhandlungen der Deutschen Physikalischen Gesellschaft
Publisher:Deutsche Physikalische Gesellschaft
Place of publication:Bad Honnef
Document Type:Conference Proceeding
Language:English
Year of publication:2017
Tag:Al₂O₃; X-Ray absorption spectroscopy; capacitance-voltage measurements; defect states; resonant photoelectron spectroscopy
First Page:S. 205
Series ; volume number:Verhandlungen der Deutschen Physikalischen Gesellschaft ; Reihe 6, Band 52,2
Faculty/Chair:Fakultät 1 MINT - Mathematik, Informatik, Physik, Elektro- und Informationstechnik / FG Angewandte Physik und Halbleiterspektroskopie
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