Nav: Home

Coffee-ring effect leads to crystallization control in semiconductors

March 03, 2017

A chance observation of crystals forming a mark that resembled the stain of a coffee cup left on a table has led to the growth of customized polycrystals with implications for faster and more versatile semiconductors.

Thin-film semiconductors are the foundation of a vast array of electronic and optoelectronic devices. They are generally fabricated by crystallization processes that yield polycrystals with a chaotic mix of individual crystals of different orientations and sizes.

Significant advances in controlling crystallization has been made by a team led by Professor Aram Amassian of Material Science and Engineering at KAUST. The group included individuals from the KAUST Solar Center and others from the University's Physical Science and Engineering Division in collaboration with Cornell University. Amassian said, "There is no longer a need to settle for random and incoherent crystallization."

The team's recent discovery began when Dr. Liyang Yu of the KAUST team noticed that a droplet of liquid semiconductor material dried to form an outer coffee-ring shape that was much thicker than the material at the center. When he induced the material to crystallize, the outer ring crystallized first.

"This hinted that local thickness matters for initiating crystallization," said Amassian, which went against the prevailing understanding of how polycrystal films form.

This anomaly led the researchers to delve deeper. They found that the thickness of the crystallizing film could be used to manipulate the crystallization of many materials (see top image). Most crucially, tinkering with the thickness also allowed fine control over the position and orientation of the crystals in different regions of a semiconductor.

"We discovered how to achieve excellent semiconductor properties everywhere in a polycrystal film," said Amassian. He explained that seeding different patterns of crystallization at different locations also allowed the researchers to create bespoke arrays that can now be used in electronic circuits (see bottom image).

This is a huge improvement to the conventional practice of making do with materials whose good properties are not sustained throughout the entire polycrystal nor whose functions at different regions can be controlled.

"We can now make customized polycrystals on demand," Amassian said.

Amassian hopes that this development will lead to high-quality, tailored polycrystal semiconductors to promote advances in optoelectronics, photovoltaics and printed electronic components. The method has the potential to bring more efficient consumer electronic devices, some with flexible and lightweight parts, new solar power generating systems and advances in medical electronics. And all thanks to the chance observation of an odd pattern in a semiconductor droplet.

The team will now explore ways to move their work beyond the laboratory through industry partnerships and research collaborations.
-end-


King Abdullah University of Science & Technology (KAUST)

Related Semiconductor Articles:

Ultrafast tunable semiconductor metamaterial created
An international team of researchers has devised an ultrafast tunable metamaterial based on gallium arsenide nanoparticles, as published by Nature Communications.
Graphene 'copy machine' may produce cheap semiconductor wafers
A new technique developed by MIT engineers may vastly reduce the overall cost of wafer technology and enable devices made from more exotic, higher-performing semiconductor materials than conventional silicon.
Method improves semiconductor fiber optics, paves way for developing devices
A new method to improve semiconductor fiber optics may lead to a material structure that might one day revolutionize the global transmission of data, according to an interdisciplinary team of researchers.
Scientists discover new 'boat' form of promising semiconductor GeSe
Princeton researchers have discovered a new form of the simple compound GeSe that has surprisingly escaped detection until now.
UNIST engineers oxide semiconductor just single atom thick
A new study, affiliated with South Korea's Ulsan National Institute of Science and Technology, has introduced a new technique that efficiently isolates circulating tumor cells from whole blood at a liquid-liquid interface.
Semiconductor-free microelectronics are now possible, thanks to metamaterials
Engineers at the University of California San Diego have fabricated the first semiconductor-free, optically-controlled microelectronic device.
Notre Dame researchers find transition point in semiconductor nanomaterials
Collaborative research at Notre Dame has demonstrated that electronic interactions play a significant role in the dimensional crossover of semiconductor nanomaterials.
Graphene key to growing 2-dimensional semiconductor with extraordinary properties
A newly discovered method for making two-dimensional materials could lead to new and extraordinary properties, particularly in a class of materials called nitrides, say the Penn State materials scientists who discovered the process.
UA organic semiconductor research could boost electronics
A team of UA researchers in engineering and chemistry has received $590,000 from the National Science Foundation to enhance the effectiveness of organic semiconductors for making ultrathin and flexible optoelectronics like OLED displays for TVs and mobile phones.
NREL theory establishes a path to high-performance 2-D semiconductor devices
Researchers at the Energy Department's National Renewable Energy Laboratory (NREL) have uncovered a way to overcome a principal obstacle in using two-dimensional (2-D) semiconductors in electronic and optoelectronic devices.

Related Semiconductor Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".