The ever-increasing demand for enhanced performance in electronic devices such as solar cells, sensors and batteries is matched by a need to find ways to make smaller electrical components.
Fine arrays of nanopillars can be patterned onto a silicon surface using a self-assembling polymer template. Copyright : A*STAR Research
Several techniques have been proposed for creating tiny, nanoscale structures on silicon, but these types of ‘nanopatterning’ tend to involve low-throughput, high-cost approaches not suited to large-scale production. Sivashankar Krishnamoorthy and co-workers at the A*STAR Institute of Materials Research and Engineering have now found a simple and robust method for nanopatterning the entire surface of a silicon wafer1.
Krishnamoorthy’s technique exploits the self-assembling properties of polymeric nanoparticles, known as reverse micelles. These unconventional particles have a structure consisting of a polar core and an outer layer of non-polar ‘arms’. Reverse micelles can form highly ordered arrays on the surface of a silicon wafer. The resulting ‘coating’ can be used as a lithographic resist to mask the silicon surface during the etching process.
Although other groups have developed similar approaches in previous studies, Krishnamoorthy and co-workers are the first to develop a process that can pattern the entire surface of a silicon wafer with highly uniform nanostructures (see image). The authors have further developed a method to quantify nanostructure variations across large areas using simple optical tools, paving the way for high-throughput nanometrology.
In an additional improvement to the process, the researchers exposed the self-assembled polymer layer to a titanium chloride vapour. The titanium chloride selectively accumulates within each micelle’s polar core. A blast of oxygen plasma then strips away the polymer to leave a pattern of tiny titanium oxide dots. This process converts a soft organic template into a hard inorganic mask much more suited to etching ultra-fine features into the silicon, producing arrays of nanopillars less than 10 nanometers apart.
The findings are expected to be highly adaptable. “Although we have demonstrated the process for creating silicon nanopillars, it is very versatile and can be readily extended to achieve nanopatterns of most other materials, for example, metals, semiconductors and polymers through appropriate post-processing of the initial copolymer templates,” explains Krishnamoorthy. "Other patterns besides nanopillars could also be created, depending on the pattern-transfer processing employed."
Krishnamoorthy and his team are already exploring the potential applications of their technique. “We are currently making use of this process to create nanodevices for sensing, data storage, and energy applications, such as batteries and solar cells,” Krishnamoorthy says.
Krishnamoorthy, S., Manipaddy, K. K., and Yap, F. L. Wafer-level self-organized copolymer templates for nanolithography with sub-50 nm feature and spatial resolutions. Advanced Functional Materials 21, 1102–1112 (2011).
The search for dark matter widens
21.03.2018 | American Institute of Physics
Scientists have a new way to gauge the growth of nanowires
19.03.2018 | DOE/Argonne National Laboratory
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
21.03.2018 | Physics and Astronomy
21.03.2018 | Materials Sciences
21.03.2018 | Life Sciences