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Indexed by:期刊论文

Date of Publication:2017-06-05

Journal:JOURNAL OF ALLOYS AND COMPOUNDS

Included Journals:SCIE、EI、Scopus

Volume:706

Page Number:495-501

ISSN No.:0925-8388

Key Words:Amorphous; Thin film; Semiconductor compounds; Short-range order

Abstract:Amorphous Fe-Si thin films showing interesting semiconductor properties can be formed over a large composition range near beta-FeSi2. In the present study, amorphous Fe100-xSix (x = 30.3 - 100) films were prepared by radio frequency magnetron co-sputtering, for the objective of clarifying the semiconducting composition range. The results on optical band gap, electrical resistivity, initial crystallization temperature, and devitrification phases all pointed to three distinct composition zones where the semiconducting behavior vary substantially, i. e., non-semiconducting 30.3 <= x <= 50, beta-FeSi2-like direct bandgap 50 < x < 87.5, and amorphous Si - like indirect bandgap 87.5 <= x <= 100. Since both semiconducting and transport properties are short-range-order relevant, an interpretation using the clusterplus- glue-atom model for the description of short-range-order amorphous structures was attempted. The nearest-neighbor clusters [Fe-Si7Fe6], [Fe-Si8Fe2], and [Si-Si-4] are derived in relevant crystalline phases epsilon-FeSi, beta-FeSi2 and Si, respectively. Using the cluster formulas for metallic glasses, i. e., a cluster being matched with one or three glue atoms, the zone boundaries were well interpreted, i. e., [Fe-Si-4] Si-3 showing the formulas corresponding to the boundary of a direct-to indirect-bandgap transition zone, supporting the dependence of semiconducting behaviors on short-range-ordering. (C) 2017 Elsevier B. V. All rights reserved.