ELECTRONICS

   

      Novel Approach for Single Molecule Electronic DNA Sequencing:

                                     

 fig:Schematic of single molecule DNA sequencing by a nanopore with phosphate-tagged nucleotides. Each of the four nucleotides will carry a different tag. During SBS, these tags, attached via the terminal-phosphate of the nucleotide, will be released into the nanopore one at a time where they will produce unique current blockade signatures for sequence determination. A large array of such nanopores will lead to high throughput DNA sequencing. (Credit: Image courtesy of Columbia University)

 DNA sequencing is the driving force behind key discoveries in medicine and biology. For instance, the complete sequence of an individual's genome provides important markers and guidelines for medical diagnostics and healthcare. Up to now, the major roadblock has been the cost and speed of obtaining highly accurate DNA sequences. While numerous advances have been made in the last 10 years, most current high-throughput sequencing instruments depend on optical techniques for the detection of the four building blocks of DNA: A, C, G and T. To further advance the measurement capability, electronic DNA sequencing of an ensemble of DNA templates has also been developed.

Hard Coating Extends the Life of New Ultrahigh-Density Storage Device:

A 3D schematic of the ultrahigh-density probe memory device. Researchers coated the tips of the probes with a thin metal film of hafnium diboride (HfB2) to reduce wear and extend the device's lifetime

 Probe storage devices read and write data by making nanoscale marks on a surface through physical contact. The technology may one day extend the data density limits of conventional magnetic and optical storage, but current probes have limited lifespans due to mechanical wear.

A research team, led by Intel Corp., has now developed a long-lasting ultrahigh-density probe storage device by coating the tips of the probes with a thin metal film.

The team's device features an array of 5,000 ultrasharp probes that is integrated with on-chip electronic circuits. The probes write tiny bits of memory as small as a few nanometers by sending short electrical pulses to a ferroelectric film, a material that can be given a permanent electric polarization by applying an electric field. High-speed data access requires that the probes slide quickly and frequently across the film. To prevent tip wear, which can seriously degrade the write-read resolution of the device, the researchers deposited a thin metal film of hafnium diboride (HfB2) on the probe tips.

As the researchers describe in the American Institute of Physics' journal Applied Physics Letters, the metal film reduces wear and enables the probe tips to retain their write-read resolution at high speeds for distances exceeding 8 kilometers -- greatly increasing the device's lifetime. The data densities of the device exceed 1 Terabit per square inch. The work is an important step toward the commercialization of a probe-based storage technology with capacities that exceed those of hard disk and solid-state drives.

Photonics: First All-Optical Nanowire Switch:

  

fig:Laser light is emitted from the end of a cadmium sulfide nanowire.

Computers may be getting faster every year, but those advances in computer speed could be dwarfed if their 1's and 0's were represented by bursts of light, instead of electricity.

Researchers at the University of Pennsylvania have made an important advance in this frontier of photonics, fashioning the first all-optical photonic switch out of cadmium sulfide nanowires. Moreover, they combined these photonic switches into a logic gate, a fundamental component of computer chips that process information.

The research was conducted by associate professor Ritesh Agarwal and graduate student Brian Piccione of the Department of Materials Science and Engineering in Penn's School of Engineering and Applied Science. Post-doctoral fellows Chang-Hee Cho and Lambert van Vugt, also of the Materials Science Department, contributed to the study.

It was published in the journal Nature Nanotechnology.

The research team's innovation built upon their earlier research, which showed that their cadmium sulfide nanowires exhibited extremely strong light-matter coupling, making them especially efficient at manipulating light. This quality is crucial for the development of nanoscale photonic circuits, as existing mechanisms for controlling the flow of light are bulkier and require more energy than their electronic analogs.

"The biggest challenge for photonic structures on the nanoscale is getting the light in, manipulating it once it's there and then getting it out," Agarwal said. "Our major innovation was how we solved the first problem, in that it allowed us to use the nanowires themselves for an on-chip light source."

The research team began by precisely cutting a gap into a nanowire. They then pumped enough energy into the first nanowire segment that it began to emit laser light from its end and through the gap. Because the researchers started with a single nanowire, the two segment ends were perfectly matched, allowing the second segment to efficiently absorb and transmit the light down its length.

"Once we have the light in the second segment, we shine another light through the structure and turn off what is being transported through that wire," Agarwal said. "That's what makes it a switch."

The researchers were able to measure the intensity of the light coming out of the end of the second nanowire and to show that the switch could effectively represent the binary states used in logic devices.

"Putting switches together lets you make logic gates, and assembling logic gates allows you to do computation," Piccione said. "We used these optical switches to construct a NAND gate, which is a fundamental building block of modern computer processing."

A NAND gate, which stands for "not and," returns a "0" output when all its inputs are "1." It was constructed by the researchers by combining two nanowire switches into a Y-shaped configuration. NAND gates are important for computation because they are "functionally complete," which means that, when put in the right sequence, they can do any kind of logical operation and thus form the basis for general-purpose computer processors.

"We see a future where 'consumer electronics' become 'consumer photonics'," Agarwal said. "And this study shows that is possible."

The research was supported by the U.S. Army Research Office and the National Institutes of Health's New Innovator Award Program.

The Pocket Radar: Thumbtack-Sized Distance and Motion Sensor Developed

                                       

                                         

The novel radar sensor has only half the size of a Euro cent coin but contains all necessary radio-frequency components

Today's parking assistant systems enable drivers to safely park their cars even in the narrowest of gaps. Such sophisticated parking aids, and also manufacturing robots which, to move about in unknown environments, require millimeter precision control, rely on precise all-around radar distance measurement. Together with the Karlsruhe Institute of Technology (KIT), the SUCCESS Consortium now has succeeded in integrating the necessary radar technology into millimeter-sized chip housings.

For the first time now, we have succeeded in integrating all relevant radio-frequency components into one chip housing," Thomas Zwick points out the advantage of this innovative technology. "Users can solder the chip onto their standard circuit boards and receive low frequency signals that can be processed without difficulty," Zwick, who heads KIT's Institute for High-frequency Technology and Electronics, goes on to explain. The sensor sends and receives electromagnetic waves having a frequency of 122 GHz, which corresponds to a wavelength of approximately two and a half millimeters. From the run time of the waves, the distance to an object that is several meters away is calculated with an accuracy of up to less than one millimeter.

In addition, the velocity of the respective object can be measured via the Doppler effect. The sensor itself, as a matter of fact, measures only 8 x 8 millimeters but contains all the necessary radio-frequency components. The output signals thus are signals of low frequency that can be processed further by means of standard electronic systems. Zwick is sure that "this compact technology will make accessible various new applications," and that "in the long run, series production could reduce costs per radar sensor unit to less than one Euro."

Beside vehicle environment detection and control of industrial robots, there are numerous other conceivable applications, for example extremely flat door or gate motion sensors that can be hidden behind the wallpaper or drilling machines switching off automatically once the desired drilling depth is reached. "Regarding the complex integration of the technology, we have been able to benefit from the broad spectrum of skills of the members of SUCCESS," Zwick smiles.

The chip itself is based on the SiGe- BiCMOS technology that is suitable for highest frequencies and was developed by IHP Innovations for High Performance Microelectronics which is member of the Leibniz Association. The chip design was provided by IHP and Silicon Radar GmbH. KIT was in charge of the design of the transmitting and receiving antennae and their integration into the small package. The thin and flexible organic carrier material of the antennae was developed by Hightec MC AG, Lenzburg, Switzerland. The Finnish company SELMIC manufactured the ceramic housing and assembled the prototype. Based on studies and analyses of various possible applications, Robert Bosch GmbH developed the system design of the sensor, integrated the control electronics, and carried out the performance tests. ST Microelectronics, Evatronix, and the University of Toronto are further members of the EU-supported consortium.

New 'ATM' Takes Old Phones and Gives Back 

Green:

With support from the NSF Small Business Innovation Research program, ecoATM of San Diego, Calif., has developed a unique, automated system that lets consumers trade in old electronic devices for reimbursement or recycling.

 When new cell phones or tablets enter the marketplace, yesterday's hot technology can quickly become obsolete--for some consumers. For others, the device still has value as an affordable alternative, or even as spare parts.

With support from the National Science Foundation (NSF), ecoATM of San Diego, Calif., has developed a unique, automated system that lets consumers trade in those devices for reimbursement or recycling.

Using sophisticated artificial intelligence developed through two NSF Small Business Innovation Research grants, ecoATM kiosks can differentiate varied consumer electronics products and determine a market value. If the value is acceptable, users have the option of receiving cash or store credit for their trade--or donating all or part of the compensation to one of several charities.

ecoATM finds second homes for three-fourths of the phones it collects, sending the remaining ones to environmentally responsible recycling channels to reclaim any rare earth elements and keep toxic components from landfills. ecoATM is certified to the eWaste environmental standards of Responsible Recycling (R2) and ISO 14001.

"The basic technologies of machine vision, artificial intelligence and robotics that we use have existed for many years, but none have been applied to the particular problem of consumer recycling," says ecoATM co-founder and NSF principal investigator Mark Bowles. "But we've done much more than just apply existing technology to an old problem--we developed significant innovations for each of those basic elements to make the system commercially viable."

The first NSF Small Business Innovation Research grant allowed ecoATM to develop artificial intelligence and diagnostics that delivered 97.5 percent accuracy for device recognition, removing human oversight and making the system viable for broad use. A follow-on NSF SBIR grant is helping ecoATM close that final 2.5 percent accuracy gap.

According to Bowles, traditional machine vision generally relies on pattern matching, pairing a new image to a known one. Pattern matching is a binary approach that cannot handle the complexity of ecoATM's evaluation process, which includes eight separate grades based on a device's level of damage.

"We are now able to tell the difference between cracked glass on a phone, which is an inexpensive fix, versus a broken display or bleeding pixels, which is generally fatal for the device," says Bowles. "We were warned by leading machine-vision experts that solving the inspecting/grading problem-with an infinite variety of possible flaws-was an impossible problem to solve. Yet with our NSF support, we solved it through several years of research and development, trial and error, use of artificial intelligence and neural network techniques."

The company's databases are now trained with images of more than 4,000 devices, and when an identification mistake occurs, the system learns from that mistake.

When a user places their device into an ecoATM kiosk, the artifical intelligence system conducts a visual inspection, identifies the device model and then robotically provides one of 23 possible connector cables for linking it to the ecoATM network (the company warns consumers to erase all personal data before recycling).

Using proprietary algorithms, the system then determines a value for the device based on the company's real-time, worldwide, pre-auction system.Within that system, a broad network of buyers have already bid in advance on the 4,000 different models in eight possible grades, so the kiosk can immediately provide compensation.

A number of robotic elements enable the kiosk to safely collect, evaluate and then store each device in a process that only takes a few minutes.

"The ecoATM project is an extremely innovative way to motivate the public with an incentive to 'do the right thing' with discarded electronics, both socially and environmentally," says Glenn Larsen, the NSF SBIR program officer overseeing the ecoATM grants. "This may change behavior from simply dumping unwanted electronics to a focus on recycling, while helping put more hi-tech devices in the hands of others that might not otherwise be able to afford or acquire them."

High Durability of Nanotube Transistors in Harsh Space Environment Demonstrated:

A locally etched back-gated field effect transistor (FET) structure with a deposited dielectric layer. Thick dielectric layers are highly susceptible to radiation induced charge build-up, which is known to cause threshold voltage shifts and increased leakage in metal-oxide semiconductor (MOS) devices. To mitigate these effects, the dielectric layer is locally etched in the active region of the back-gated FET. A gate dielectric material is then deposited (depicted in red) over the entire substrate.

"One of the primary challenges for space electronics is mitigating the susceptibility of prolonged exposure to radiation that exists in the charged particle belts that encircle Earth," said Cory Cress, materials research engineer. "These are the first controlled demonstrations showing little performance degradation and high tolerance to cumulative ionizing radiation exposure."

Radiation effects take two forms, transient effects and cumulative effects. The former, referred to as single effect transients (SETs), result from a direct strike by an ionizing particle in space that causes a current pulse in the device. If this pulse propagates through the circuit it can cause data corruption that can be extremely detrimental to someone that relies on that signal, such as a person using GPS for navigation. NRL researchers have recently predicted that such effects are nearly eliminated for SWCNT-based nanoelectronics due to their small size, low density, and inherent isolation from neighboring SWCNTs in a device.

The cumulative effects in traditional electronics results from trapped charges in the oxides of the devices, including the gate oxide and those used to isolate adjacent devices, the latter being primary source of radiation-induced performance degradation in state-of-the-art complementary metal-oxide semiconductor (CMOS) devices. The effect is manifested as a shift in the voltage needed to turn the transistor on or off. This initially results in power leakage, but can eventually cause failure of the entire circuit.

By developing a SWCNT structure with a thin gate oxide made from thin silicon oxynitride, NRL researchers recently demonstrated SWCNT transistors that do not suffer from such radiation-induced performance changes. This hardened dielectric material and naturally isolated one-dimensional SWCNT structure makes them extremely radiation tolerant.

The ability for SWCNT-based transistors to be both tolerant to transient and cumulative effects potentially enables future space electronics with less redundancy and error-correction circuitry, while maintaining the same quality of fidelity. This reduction in overhead alone would greatly reduce power and improve performance over existing space-electronic systems even if the SWCNT-based transistors operate at the same speed as current technologies. Even greater benefits are foreseeable in the future, once devices are developed that exceed the performance of silicon-based transistors.