Crystal film growth: Nanosheets extend epitaxial growth applications

Dec 17, 2013
Crystal film growth: Nanosheets extend epitaxial growth applications
Schematic illustration of nanosheet structures for Ca2Nb3O10-, Ti0.87O20.52-, and MoO2δ− nanosheets and corresponding crystal planes of SrTiO3.

Molecularly thin two-dimensional crystals can alleviate the lattice matching restrictions of epitaxial crystalline thin film growth, as reported by researchers in Japan.

Epitaxial growth has become increasingly important for growing crystalline thin films with tailored electronic, optical and magnetic properties for technological applications. However, the approach is limited by the high structural similarities required between an underlying substrate and a growing crystal layer on top of it. Takayoshi Sasaki and colleagues at the International Center for Materials Nanoarchitectonics (MANA) and the University of Tokyo in Japan demonstrate how using two-dimensional materials they can extend the versatility of epitaxial growth techniques.

In 1984, Prof. Koma at the University of Tokyo proposed that certain layered materials such as mica or graphite can be easily cleaved to produce surfaces with no dangling bonds that would alleviate the lattice matching requirements for epitaxial growth. Interactions between adatoms on these cleaved materials would be more prominent compared with growth on single-crystal substrates since the van der Waals interactions are weak. However, the variety of suitable cleaved surfaces is limited and handling them can be difficult.

With the increasing attention on two-dimensional over recent years, Takayoshi Sasaki and colleagues decided to look into molecularly thin two-dimensional crystals as possible seed layers to alleviate lattice matching requirements in a manner similar to Koma's van der Waals epitaxy. They deposited nanosheets of either Ca2Nb3O10-, Ti0.87O20.52-, or MoO2δ- as a highly organised monolayers onto amorphous glass. On these different surfaces, they grew different orientations of SrTiO3, an important perovskite for various technological applications. The approach demonstrated the ability to grow different orientations of SrTiO3 with a high level of precision.

The researchers suggest that in the future, it would be of great interest to achieve more sophisticated control of growth geometry using nanosheets with a complex structure. They add, "Such advanced design, hardly realized with present technology, will pave a new way for further development of crystal engineering."

Explore further: Two-dimensional nanosheets enable high-quality thin film orientation control

More information: "Versatile van der Waals epitaxy-like growth of crystal films using two-dimensional nanosheets as a seed layer: Orientation tuning of SrTiO3 films along three important crystallographic axes of (100), (110) and (111) on glass substrate," Tatsuo Shibata, Hikaru Takano, Yasuo Ebina, Dae Sung Kim, Tadashi C. Ozawa, et al, 2013 J. Mater. Chem. C. DOI: 10.1039/C3TC31787K

Provided by International Center for Materials Nanoarchitectonics

not rated yet
add to favorites email to friend print save as pdf

Related Stories

New research uncovers path to defect-free thin films

Sep 20, 2012

(Phys.org)—A team led by Oak Ridge National Laboratory's Ho Nyung Lee has discovered a strain relaxation phenomenon in cobaltites that has eluded researchers for decades and may lead to advances in fuel cells, magnetic ...

Growing thin films of germanium

Sep 06, 2013

Researchers have developed a new technique to produce thin films of germanium crystals—key components for next-generation electronic devices such as advanced large-scale integrated circuits and flexible ...

Recommended for you

Thinnest feasible nano-membrane produced

9 hours ago

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

12 hours ago

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Making 'bucky-balls' in spin-out's sights

Apr 16, 2014

(Phys.org) —A new Oxford spin-out firm is targeting the difficult challenge of manufacturing fullerenes, known as 'bucky-balls' because of their spherical shape, a type of carbon nanomaterial which, like ...

User comments : 0

More news stories

Thinnest feasible nano-membrane produced

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...