Thu, Aug 24, 2017 | updated 05:03 AM IST

Make way for brighter, more efficient green LEDs

Updated: Aug 01, 2016 15:58 IST      
Make way for brighter, more efficient green LEDs

Washington D.C, Aug 1 (ANI): A team of researchers has come up with a new method for making brighter and more efficient green light-emitting diodes (LEDs).

Using an industry-standard semiconductor growth technique, researchers at the University of Illinois at Urbana Champaign created gallium nitride (GaN) cubic crystals grown on a silicon substrate that are capable of producing powerful green light for advanced solid-state lighting.

"This work is very revolutionary as it paves the way for novel green wavelength emitters that can target advanced solid-state lighting on a scalable CMOS-silicon platform by exploiting the new material, cubic gallium nitride," said researcher Can Bayram.

Bayram noted, "The union of solid-state lighting with sensing (e.g. detection) and networking (e.g. communication) to enable smart (i.e. responsive and adaptive) visible lighting, is further poised to revolutionize how we utilize light. And CMOS-compatible LEDs can facilitate fast, efficient, low-power, and multi-functional technology solutions with less of a footprint and at an ever more affordable device price point for these applications."

Typically, GaN forms in one of two crystal structures: hexagonal or cubic. Hexagonal GaN is thermodynamically stable and is by far the more conventional form of the semiconductor. However, hexagonal GaN is prone to a phenomenon known as polarization, where an internal electric field separates the negatively charged electrons and positively charged holes, preventing them from combining, which, in turn, diminishes the light output efficiency.

Until now, the only way researchers were able to make cubic GaN was to use molecular beam epitaxy, a very expensive and slow crystal growth method when compared to the widely used metal-organic chemical vapor deposition (MOCVD) method that Bayram used.

Bayram and his graduate student Richard Liu made the cubic GaN by using lithography and isotropic etching to create a U-shaped groove on Si (100). This non-conducting layer essentially served as a boundary that shapes the hexagonal material into cubic form.

"Our cubic GaN does not have an internal electric field that separates the charge carriers--the holes and electrons," explained Liu. "So, they can overlap and when that happens, the electrons and holes combine faster to produce light."

Enhanced green LEDs aren't the only application for Bayram's cubic GaN, which could someday replace silicon to make power electronic devices found in laptop power adapters and electronic substations, and it could replace mercury lamps to make ultra-violet LEDs that disinfect water.

The study appears in the journal Applied Physics Letters. (ANI)

USA all set to witness the great American Solar eclipse

Updated: Aug 21, 2017 18:59 IST     

New York [USA], August 21 (ANI): People of the United States are all set to see a total solar eclipse, which will take place on Monday, 10.30 pm, according to Indian Standard Time.

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Washington D.C. [USA], Aug 21 (ANI): Soldiering in arctic conditions is tough, but it will not remain so for long now as a team of researchers is all set to all set to change the game.

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Washington D.C. [USA], Aug 20 (ANI): Through analysis of volcanic tracks, a team of researchers has found that hot spots like those that formed the Hawaiian Islands do not move as quickly as previously thought.

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New Delhi [India], Aug 19 (ANI): Vijnana Bharati's JNU chapter commenced with a Dr Vikram Sarabhai Memorial lecture, celebrating the National Remote Sensing Day in the university's School of Environmental Sciences (SES).

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Indian researchers discover two new species of earthworm

Updated: Aug 19, 2017 06:57 IST     

New Delhi [India], Aug 19 (ANI): A team of Indian researchers has discovered two new primitive species of earthworm in the Western Ghats mountain ranges in Kerala.

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New Delhi [India], Aug 18 (ANI): Two recent studies have highlighted effective ways of reducing antibiotic consumption without any disadvantage for patients.

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Japan introduces solar heat-blocking pavements

Updated: Aug 17, 2017 14:10 IST     

Tokyo [Japan], Aug.16 (ANI): The host city of Olympic and Paralympic Games in 2020, Tokyo is working on heat blocking methods during the summer.

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New Delhi [India], August 17 (ANI): The Fortis Foundation recently launched two charitable medical dispensaries at the Anubhavi Ashram in Haridwar, Uttarakhand and at the Aggarwal Dharamshala in New Delhi.

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Nagpur (Maharashtra) [India], Aug.15 (ANI): The public sector Oil and Natural Gas Coroporation (ONGC) has extended a support of Rs 100 crore to turn the vision of affordable world class cancer care facilities in Central India into reality.

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Are tidally-locked exoplanets more common than believed?

Updated: Aug 15, 2017 10:16 IST     

Washington D.C. [USA], Aug 15 (ANI): There's a possibility for a lot more exoplanets to be tidally locked, according to new research.

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Robots lend a helping hand to esophageal surgeons

Updated: Aug 13, 2017 05:25 IST     

Washington D.C. [USA], Aug 13 (ANI): Robots are no longer just useful tools to make life easy and convenient; turns out, some of them can offer key advantages in esophageal surgeries.

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Are USB connections putting your data at risk?

Updated: Aug 11, 2017 04:21 IST     

Washington D.C. [USA], Aug 11 (ANI): Turns out, USB connections, the most common interface used globally to connect external devices to computers, make snooping easy.

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Turns out, you can catch 'Science' bug from peers

Updated: Aug 10, 2017 07:17 IST     

Washington D.C. [USA], Aug 10 (ANI): According to a recent study, developing an interest in Science as is simple as sitting next to a bunch of students fascinated by the topic.

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Washington D.C. [USA], Aug 9 (ANI): During a walk near a reservoir in a small Japanese town, amateur collectors made the discovery of their lives - the first and oldest fossil bird ever identified in their country.

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Ocean's fastest shark at risk of being 'overfished'

Updated: Aug 09, 2017 01:46 IST     

Washington D.C. [USA], Aug 9 (ANI): Overfishing is putting the ocean's fastest shark at risk, according to a recent research.

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20-month-olds can understand difference between two languages

Updated: Aug 08, 2017 07:12 IST     

Washington D.C. [USA], Aug 8 (ANI): Are two languages at a time too much for the infant mind? According to a recent study, babies as young as 20 months can understand a lot more than you'd think.

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Washington D.C. [USA], August 7 (ANI): Researchers have developed a learning method to change cognitive function by manipulating connections in the brain.

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Kicking butts to the curb

Updated: Aug 07, 2017 00:57 IST     

Washington D.C. [USA], Aug 7 (ANI): Cigarette butts are more than mere litter and now, a team of scientists has found a way to pave over the big problem.

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Desert tortoises can't take heat of roadside fencing

Updated: Aug 06, 2017 13:55 IST     

Washington D.C. [USA], August 6 (ANI): US researchers have revealed that roadside fencing, which is meant to help desert tortoise, can actually overheat them leading to their death.

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Scientists unveil how brain works with the help of magic

Updated: Aug 02, 2017 14:58 IST     

Washington D.C. [USA], August 2 (ANI): To tap into brain's 'out-of-the box' thinking, scientists are now relying on magic tricks and illusions.

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