PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

World's first large(wafer)-scale production of III-V semiconductor nanowire

2013-06-10
(Press-News.org) The research team demonstrated a novel method to epitaxially synthesize structurally and compositionally homogeneous and spatially uniform ternary InAsyP1-y nanowire on Si at wafer-scale using metal-organic chemical vapor deposition (MOCVD). The high quality of the nanowires is reflected in the remarkably narrow PL and X-ray peak width and extremely low ideality factor in the InAsyP1-y nanowire/Si diode.

A nanowire is a nanostructure with a diameter of the order of a nanometer (10-9 meters). Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. Technology related to nanowires has been selected as one of the 10 Breakthrough Technologies of 2004 by MIT Technology Review.

High-aspect-ratio semiconductors have led to significant breakthroughs in conventional electrical, optical, and energy harvesting devices. Among such structures, III-V semiconductor nanowires offer unique properties arising from their high electron mobility and absorption coefficients, as well as their direct bandgaps.

A common technique for creating a nanowire is Vapor-Liquid-Solid (VLS) synthesis. This process can produce crystalline nanowires of some semiconductor materials. However, metal catalysts, usually expensive noble metals, should be used for initiating the VLS mechanism. In addition, these metal catalysts are known to significantly degrade the quality of semiconductor nanowires by creating deep levels, thus limiting practical applications of nanowires into opto-electronic devices.

In this work, however, Prof. Choi's group developed a novel technique of growing III-V semiconductor nanowires without metal catalysts or nano-patterning. Metal-organic chemical vapor deposition (MOCVD, AIXTRON A200) was used for the growth of the InAsyP1-y. 2 inch Si (111) wafer was cleaned with buffer oxide etch for 1 minute and deionized (DI) water for 2 seconds. Then, the wafer was immediately dipped in poly-L-lysine solution (Sigma-Aldrich inc.) for 3 minutes then rinsed in DI water for 10 seconds. The Si substrate was then loaded into the MOCVD reactor without any delay. The reactor pressure was lowered to 50 mbar with 15liter/min of hydrogen gas flow. Then the reactor was heated to growth temperatures (570 – 630 ℃), and stabilized for 10 minutes.

Kyoung Jin Choi, Associate Professor at Ulsan National Institute of Science and Technology (UNIST), Korea, and Xiuling Li, Professor at University of Illinois, U.S.A. led the research and this description of the new research was published on the web on May 7 in ACS Nano. (Title: Wafer-Scale Production of Uniform InAsyP1-y Nanowire Array on Silicon for Heterogeneous Integration).

"If we develop new technology which manages the density of nanowire and bandgap energy with further study, it is also possible to produce high-efficiency & low-cost large scale solar cells," said Prof. Choi. "This technology will give us a chance to lead the research on the new renewable energy."



INFORMATION:

This work was supported by the Future-based Technology Development Program (Nano Fields) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology.



ELSE PRESS RELEASES FROM THIS DATE:

Suicide risk factors mapped

2013-06-10
A landmark study of the Swedish population has given a clearer picture of important risk factors for suicide. The study, a collaboration between Lund University in Sweden and Stanford University, showed that the rate of suicide among men is almost three times that of women. Being young, single and having a low level of education were stronger risk factors for suicide among men, while mental illness was a stronger risk factor among women. Unemployment was the strongest social risk factor among women, whereas being single was the strongest among men. Because the study ...

Catching individual molecules in a million with optical antennas inside nano-boxes

2013-06-10
A single cell in our body is composed of thousands of millions of different biomolecules that work together in an extremely well-coordinated way. Likewise, many biological and biochemical reactions occur only if molecules are present at very high concentrations. Understanding how all these molecules interact with each other is key to advancing our knowledge in molecular and cell biology. This knowledge is of central and fundamental importance in the quest for the detection of the earliest stages of many human diseases. As such, one of ultimate goals in Life Sciences and ...

Study reveals leakage of carbon from land to rivers, lakes, estuaries and coastal regions

2013-06-10
When carbon is emitted by human activities into the atmosphere it is generally thought that about half remains in the atmosphere and the remainder is stored in the oceans and on land. New research suggests that human activity could be increasing the movement of carbon from land to rivers, estuaries and the coastal zone indicating that large quantities of anthropogenic carbon may be hidden in regions not previously considered. The research, published in Nature Geoscience and led by researchers from the Université Libre de Bruxelles, the University of Exeter, Laboratoire ...

The secret life of knots

2013-06-10
Nanotechnologies require a detailed knowledge of the molecular state. For instance, it is useful to know when and how a generic polymer, a long chain of polymers (chain of beads), knots. The study of molecular entanglement is an important field of study as the presence of knots affects its physical properties, for instance the resistence to traction. Previous studies had mainly obtained "static" data on the knotting probability of such molecules. In other words, they focused on the likelihood that a polymer may knot. The novelty of the study carried out by Micheletti ...

Uni Basel researchers discover master regulator in cancer metastasis

2013-06-10
The predominant cause of death in cancer patients is metastasis, the formation of secondary tumors in other organs like the brain, liver, and lungs. Cancer cells detach from the original primary tumor and reach a single cell or group of cells in another organ. The cells of the body normally remain in place through adhering to an extracellular substance. However, cancer cells learn how to release themselves from these bonds and invade surrounding tissues, blood, and the lymphatic system. The transformation of sedentary, specialized cells into wandering, invasive, and ...

Do antidepressants impair the ability to extinguish fear?

2013-06-10
An interesting new report of animal research published in Biological Psychiatry suggests that common antidepressant medications may impair a form of learning that is important clinically. Selective serotonin reuptake inhibitors, commonly called SSRIs, are a class of antidepressant widely used to treat depression, as well as a range of anxiety disorders, but the effects of these drugs on learning and memory are poorly understood. In a previous study, Nesha Burghardt, then a graduate student at New York University, and her colleagues demonstrated that long-term SSRI treatment ...

Treatment of mental illness lowers arrest rates, saves money

2013-06-10
Research from North Carolina State University, the Research Triangle Institute (RTI) and the University of South Florida shows that outpatient treatment of mental illness significantly reduces arrest rates for people with mental health problems and saves taxpayers money. "This study shows that providing mental health care is not only in the best interest of people with mental illness, but in the best interests of society," says Dr. Sarah Desmarais, an assistant professor of psychology at NC State and co-author of a paper describing the research. The researchers wanted ...

How Archaea might find their food

2013-06-10
The microorganism Methanosarcina acetivorans lives off everything it can metabolize into methane. How it finds its sources of energy, is not yet clear. Scientists at the Ruhr-Universität Bochum together with colleagues from Dresden, Frankfurt, Muelheim and the USA have identified a protein that might act as a "food sensor". They characterized the molecule in detail and found both similarities and differences to the system that is responsible for the search for food in bacteria. The team reports in the Journal of Biological Chemistry. MsmS has a different function to that ...

Eww! Only 5 percent of us wash hands correctly

2013-06-10
VIDEO: A study by Michigan State University researchers found that only 5 percent of people who used the bathroom washed their hands long enough to kill the germs that can cause... Click here for more information. EAST LANSING, Mich. — Remember Mom's advice about washing your hands thoroughly after using the restroom? Apparently not. A new study by Michigan State University researchers found that only 5 percent of people who used the bathroom washed their hands long ...

Split liver transplants for young children proven to be as safe as whole organ transplantation

2013-06-10
Boston, Mass.— A new study shows that when a liver from a deceased adult or adolescent donor is split into two separate portions for transplantation—with the smaller portion going to a young child and the larger to an adult—the smaller portion used for the child will last just as long as if the child had received a whole organ from a donor close to his size. The data, collected and analyzed by a team led by Boston Children's Hospital researchers Heung Bae Kim, MD, and Ryan Cauley, MD, MPH, was published online in Liver Transplantation, a journal of the American Association ...

LAST 30 PRESS RELEASES:

Milky Way-like galaxy M83 consumes high-speed clouds

Study: What we learned from record-breaking 2021 heat wave and what we can expect in the future

Transforming treatment outcomes for people with OCD

Damage from smoke and respiratory viruses mitigated in mice via a common signaling pathway

New software tool could help better understand childhood cancer

Healthy lifestyle linked to lower diverticulitis risk, irrespective of genetic susceptibility

Women 65+ still at heightened risk of cervical cancer caused by HPV

‘Inflammatory’ diet during pregnancy may raise child’s diabetes type 1 risk

Effective therapies needed to halt rise in eco-anxiety, says psychology professor

Nature-friendly farming boosts biodiversity and yields but may require new subsidies

Against the odds: Endometriosis linked to four times higher pregnancy rates than other causes of infertility, new study reveals

Microplastics discovered in human reproductive fluids, new study reveals

Family ties and firm performance: How cousin marriage traditions shape informal businesses in Africa

Novel flu vaccine adjuvant improves protection against influenza viruses, study finds

Manipulation of light at the nanoscale helps advance biosensing

New mechanism discovered in ovarian cancer peritoneal metastasis: YWHAB restriction drives stemness and chemoresistance

New study links blood metabolites and immune cells to increased risk of urolithiasis

Pyruvate identified as a promising therapeutic agent for ulcerative colitis by targeting cytosolic phospholipase A2

New insights into the clinical impact of IKBKG mutations: Understanding the mechanisms behind rare immunodeficiency syndromes

Displays, imaging and sensing: New blue fluorophore breaks efficiency records in both solids and solutions

Sugar, the hidden thermostat in plants

Personality can explain why some CEOs earn higher salaries

This puzzle game shows kids how they’re smarter than AI

Study suggests remembrances of dead played role in rise of architecture in Andean region

Brain stimulation can boost math learning in people with weaker neural connections

Inhibiting enzyme could halt cell death in Parkinson’s disease, study finds

Neurotechnology reverses biological disadvantage in maths learning

UNDER EMBARGO: Neurotechnology reverses biological disadvantage in maths learning

Scientists target ‘molecular machine’ in the war against antimicrobial resistance

Extending classical CNOP method for deep-learning atmospheric and oceanic forecasting

[Press-News.org] World's first large(wafer)-scale production of III-V semiconductor nanowire