Home >

news Help

Publication Information


Title
Japanese: 
English:Graphoepitaxy of ZnO: novel selection rule of domain formation on nanopatterned glass surface 
Author
Japanese: 大友 明, 入野 将昂, 大橋 一輝, 大島 孝仁.  
English: A. Ohtomo, M. Irino, K. Ohashi, T. Oshima.  
Language English 
Journal/Book name
Japanese: 
English: 
Volume, Number, Page        
Published date Dec. 1, 2014 
Publisher
Japanese: 
English: 
Conference name
Japanese: 
English:2014 Materials Research Society Fall Meeting 
Conference site
Japanese:ボストン 
English:Boston 
Official URL http://www.mrs.org/fall2014/
 
Abstract ZnO and related materials have excellent optical and electronic properties, and recent advancements in epitaxial growth technique have spurred the investigation of these materials for applications such as ultraviolet light-emitting diodes and invisible transistors. Although reliable technique for p-type doping into ZnO is not yet completed, the crystalline quality and materials purity is now approaching ultimate limits− the fractional quantum Hall effect has been observed in ultraclean ZnO/MgZnO interfaces. The majority of the applications presently envisaged can essentially be realized if single-crystalline layers glow on low-cost glass and polymer substrates in a fashion of graphoepitaxy. The notion of graphoepitaxy has been applied for many classes of materials, including semiconductors, metals, molecular compounds, and alkali halides. A rational mechanism of crystal orientations is induced by the fact that nucleation occurs under geometric constraint in a grating lithographically fabricated on the glass surface. Here we study this for the ionic oxide semiconductor, hexagonal ZnO on a quartz substrate with a square-wave relief grating structure. The epitaxial structure was obtained by two-step growth; pulsed-laser deposition (PLD) of a c-axis oriented, homogeneous nucleation layer, followed by mist chemical vapor deposition (Mist CVD) of an in-plane oriented, a few microns domains (a few microns). Surprisingly, rotational symmetry of the domains was found to be twisted by 90º from right angles commonly found in graphoepitaxy (i.e., crystal facet m-planes parallel to the side walls). We investigated surface morphology for the growth-interrupted films to identify that the m-plane facets indeed appeared perpendicular to side walls. The details of novel selection rule of the domain formation and the electronic properties of the obtained films will be presented.

©2007 Tokyo Institute of Technology All rights reserved.