Band alignment and effective work function of atomic‐layer deposited VO2 and V2O5 films on SiO2 and Al2O3. Issue 1 (20th November 2014)

• Record Type: Journal Article
• Authors: Cerbu, F.; Chou, H.‐S.; Radu, I. P.; Martens, K.; Peter, A. P.; Afanas'ev, V. V.; Stesmans, A.
• Is Part Of: Physica status solidi. Volume 12:Issue 1/2(2015)
• Page Start: 238
• Page End: 241
• Publication Date: 2014-11-20
• Subjects: Solid state physics -- Congresses; Solid state physics -- Periodicals; Solid state physics; Conference proceedings; Periodicals; 530.41
• DOI: 10.1002/pssc.201400037
• Languages: English
• ISSNs: 1862-6351

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The effective work function (EWF) and the energy position of the valence band in 20‐40‐nm thick VO₂and V₂O₅layers grown by atomic layer deposition (ALD) on top of insulating SiO₂ and γ‐Al₂O₃ films were evaluated using the comparison between capacitance‐voltage and internal photoemission measurements. From the capacitance measured at different temperatures on the metal‐VO₂(V₂O₅)‐insulator‐silicon and metal‐insulator‐silicon diodes we found that the both studied vanadium oxides have the same EWF as gold electrodes evaporated on the same oxides. This result is further collaborated by the internal photoemission experiments at the VO₂/SiO₂ and V₂O₅/SiO₂ interfaces which indicate the energy barrier between the top of the vanadium oxide valence band (in the insulating phase) and the insulator conduction band to be 4.1 ± 0.1 eV. Since the transition from the narrow‐gap VO₂ to the wide‐gap V₂O₅ oxide causes no change in the WF or in the photoemission threshold, we conclude that the ALD‐grown VO₂ in its insulating phase represents a a heavily‐doped semiconductor which becomes metallic upon metal‐insulator transition without significant EWF change. (© 2015 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)</p> </abstract>