Bio-inspired way to grow graphene for electronic devices


BioGraphene-320Dr. Gao (left) and research assistant Ms Lim Xiao Fen working on the wafer-scale graphene growth and transfer in the Graphene Research Centre’s clean roomGraphene, a form of two-dimensional carbon, has many desirable properties that make it a promising material in many applications. However, its production especially for high-end electronics such as touch screens faces many challenges. This may soon change with a fresh approach developed by National Univ. of Singapore (NUS) researchers that mimics nature.

Inspired by how beetles and tree frogs keep their feet attached to submerged leaves, the findings published recently in Nature revealed a new method that allows both the growth and transfer steps of graphene on a silicon wafer. This technique enables the graphene to be applied in photonics and electronics, for devices such as optoelectronic modulators, transistors, on-chip biosensors and tunnelling barriers.

Professor Loh Kian Ping, Head of the NUS Department of Chemistry, led a team to come up with the one-step method to grow and transfer high-quality graphene on silicon and other stiff substrates. This promises the use of graphene in high-value areas where no technique currently exists to grow and transfer graphene with minimal defects for use in semiconductors.

Prof Loh, who is also a Principal Investigator with the Graphene Research Centre at NUS Faculty of Science, explained: “Although there are many potential applications for flexible graphene, it must be remembered that to date, most semiconductors operate on “stiff” substrates such as silicon and quartz.”

Thus, a transfer method with the direct growth of graphene film on silicon wafer is needed for enabling multiple optoelectronic applications, he said.

In the process called “face-to-face transfer”, Dr. Gao Libo, the first author who is with the Graphene Research Centre, grew graphene on a copper catalyst layer coating a silicon substrate. After growth, the copper is etched away while the graphene is held in place by bubbles that form capillary bridges, similar to those seen around the feet of beetles and tree frogs attached to submerged leaves. The capillary bridges help to attach the graphene to the silicon surface and prevent its delamination during the etching of the copper catalyst.

The novel technique can potentially be deployed in batch-processed semiconductor production lines, such as the fabrication of large-scale integrated circuits on silicon wafers.

The researchers will be fine-tuning the process to optimise the high throughput production of large diameter graphene on silicon, as well as target specific graphene-enabled applications on silicon. They are also looking at applying the techniques to other two-dimensional films.

Source: National Univ. of Singapore

Solar Panel Makers Need Equipment Upgrades to Survive Shakeout


With overcapacity of 82%, companies need innovative tools to differentiate from cheaper Chinese rivals, says Lux Research.

English: Thin-film PV array

English: Thin-film PV array (Photo credit: Wikipedia)

BOSTON, Oct 25, 2012 (BUSINESS WIRE) — Reeling from a glut of production capacity, makers of solar panels need to acquire innovative production equipment in order to cut costs, increase margins, and offer differentiated products, according to Lux Research.

This year, global capacity utilization is at 55% for crystalline silicon (x-Si) module production, 70% for cadmium telluride (CdTe) and 80% for copper indium gallium (di) selenide (CIGS). Consequently, cell and module manufacturers are turning to core product differentiation to revamp margins and fend off low-cost Chinese competition.

“Across the industry there is recognition that innovation is needed to survive a shakeout,” said Fatima Toor, Lux Research Analyst and the lead author of the report titled, “Turning Lemons into Lemonade: Opportunities in the Turbulent Photovoltaic Equipment Market.” “Equipment suppliers have a vital role to play in enabling that innovation.”

Lux Research analysts examined the PV production equipment landscape to identify opportunities for innovation. Among their findings:

— There’s opportunity in reducing silicon costs. Current wafer sawing techniques waste silicon; in contrast, technologies, such as direct solidification and epitaxial silicon eliminate the need for wafer sawing. Emerging quasi-monocrystalline silicon (qc-Si) ingot growth enables 40% cheaper c-Si wafers.

— In CIGS, standardization is key. CIGS thin-film PV relies on custom equipment today. However, off-the-shelf tools and improved throughput will drive higher efficiencies, performance and yield – lowering capex and helping manufacturers attain scale and competitive production costs.

— New cell designs lead to equipment upgrades. Emerging cell designs, such as selective emitter (SE) and heterojunction with intrinsic thin layer (HIT) present potential for high efficiencies. However, they require new tools, and as a result, 60% to 70% of new equipment sales are for the cell production equipment.

The report, titled “Turning Lemons into Lemonade: Opportunities in the Turbulent Photovoltaic Equipment Market,” is part of the Lux Research Solar Components Intelligence service.

About Lux Research

Lux Research provides strategic advice and on-going intelligence for emerging technologies. Leaders in business, finance and government rely on us to help them make informed strategic decisions. Through our unique research approach focused on primary research and our extensive global network, we deliver insight, connections and competitive advantage to our clients. Visit http://www.luxresearchinc.com for more information.

SOURCE: Lux Research

Note To Readers: We have been following a ‘disruptive nanotechnology’ company, researching and developing a ‘3rd Generation’ of solar cells based in part on low-cost quantum dots and reduced input cost printing techniques. Below is a short excerpt from a website, a link also provided below. Perhaps, with innovation such as this, the U.S. Solar industry can become the clear leader in providing grid competitive renewable energy. Perhaps ….        Cheers!  – BWH-

Solterra Renewable Technologies  

http://www.solterrasolarcells.com/corporate_vision.php?ID=11

“Solterra will be producing and distributing a Thin Film Quantum Dot PV Solar Cell which is differentiated from other PV cells by a unique technology that results in lower cost, higher efficiency, and broader spectral performance.  Solterra’s Quantum Dot Solar Cell achieves a dramatically lower manufacturing cost per watt because no vacuum equipment is required, no expensive silicon is required and low-cost screen printing and/or inkjet techniques are used on inexpensive substrates. Secondly, the Solterra Thin Film Quantum Dot Solar Cell has the potential to generate multiple excitons from each proton providing the potential for exponential improvements in conversion efficiency. Third, Solterra’s PV cell is not only more efficient in the early morning and late afternoon compared to crystalline silicon PV cells, but it also has the potential to harvest light energy in the infrared and ultraviolet spectra.