Bowing Character in Wurtzite ZnO-Based Ternary Alloys
Source: Journal of Electronic Materials, Volume 41, Number 11, November 2012 , pp. 3111-3118(8)
Abstract:The existence and origins of the bandgap bowing character in the wurtzite ZnO-based ternary alloys are theoretically investigated. The tight-binding method with minimal sp3 basis set is used to calculate the band structures, density of electronic states, and constituent charge states of both common-cation ZnO1−x S x and common-anion Zn1−x Mg x O ternary alloys. The experimental data show that a well-pronounced bowing effect is induced in the common-cation case, whereas there is no apparent bowing effect in the common-anion case. The present investigation indicates that the bowing effect in the former case may result from competition between anions trapping charge made available by cations. The disappearance of this competition, in the case of common-anion alloys, eliminates the possibility of bowing, thus leading to the observed linear behavior. Furthermore, the electronegativity and its discrepancy between the two anion types are expected to play a dominant role in the magnitude of the bowing parameter. The excellent fit between our theoretical results and the available photoluminescence data support this model.
Document Type: Research Article
Affiliations: 1: Physics Department, UAE University, P.O. Box 17551, Al-Ain, United Arab Emirates, Email: firstname.lastname@example.org 2: Mechanical Engineering Department, UAE University, P.O. Box 17555, Al-Ain, United Arab Emirates 3: Physics Department, UAE University, P.O. Box 17551, Al-Ain, United Arab Emirates
Publication date: November 1, 2012