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Title
Japanese: 
English:Epitaxial structures of band-gap-engineered α-(CrxFe1-x)2O3 (0 ≤x≤1) films grown on C-plane sapphire 
Author
Japanese: 増子 尚徳, 大島 孝仁, 大友 明.  
English: H. Mashiko, T. Oshima, A. Ohtomo.  
Language English 
Journal/Book name
Japanese: 
English:Japanese Journal of Applied Physics 
Volume, Number, Page Vol. 51    11PG11-1-5   
Published date Nov. 20, 2012 
Publisher
Japanese:応用物理学会 
English:The Japan Society of Applied Physics 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL http://iopscience.iop.org/1347-4065/51/11S/11PG11
 
DOI https://doi.org/10.1143/JJAP.51.11PG11
Abstract Solid solutions of α-Cr2O3 and α-Fe2O3 are novel oxide semiconductors exhibiting narrower band gaps than those of the end members. We have investigated the heteroepitaxial growth and crystalline structure of pulsed-laser deposited α-(CrxFe1-x)2O3 films on c-plane sapphire substrates. Under the growth condition optimized for α-Fe2O3, reflection high-energy electron diffraction intensity oscillations were observable for both α-Fe2O3 and α-Cr2O3, enabling us to control film thickness in a layer-by-layer fashion. The composition dependence of the epitaxial structures, including phase purity, orientation, strain, and in-plane rotation domain, was characterized by X-ray diffraction to reveal a defect-free composition range (0 ≤x ≤0.50). The films with 0.60 ≤x ≤1 were found to have 180°-rotation domains. The absorption spectra of α-(Cr0.50Fe0.50)2O3 solid solution (corundum) and superlattice (nominally composed ilmenite) films are compared with those of end members and an α-Fe2O3/α-Cr2O3 bilayer film to elucidate the origin of the band-gap narrowing.

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