Title: Effect of the composition on the bandgap width of high-kappa MexTiyOz (Me = Hf, Ta, Sr) layers
Authors: Wang, Wan-Chih ×
Badylevich, Mikhail
Afanas'ev, Valeri
Stesmans, Andre
Popovici, M
Tomida, K
Menou, N
Kittl, Jorge
Lukosius, M
Kaynak, C. Baristiran
Wenger, Ch #
Issue Date: Jun-2011
Publisher: Elsevier Sequoia
Series Title: Thin Solid Films vol:519 issue:17 pages:5730-5733
Abstract: To explore the possibility of bandgap engineering in Ti-oxide based insulators, we investigated the effect of added cations of another kind (Hf, Ta, Sr) on the optical absorption and photoconductivity of thin titanate films. A bandgap of 3.1-3.4 eV, typical for pure polycrystalline TiO2, was found in crystallized SrxTiyOz of different composition as well as in amorphous Ta2Ti3Oz. By contrast, the gap width of Hf titanates increases starting from 3.5 eV for 30% Hf/(Hf + Ti) to 4.2 eV for 84% Hf/(Hf + Ti). We suggest that this gap widening is associated with reduced interaction between electron states of neighboring Ti cations as influenced by a wide-gap (E-g = 5.6 eV) HfO2 sub-network. (C) 2011 Elsevier B.V. All rights reserved.
ISSN: 0040-6090
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Semiconductor Physics Section
× corresponding author
# (joint) last author

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