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IR sensor startup preps smartphone bid By Peter Clarke Pyreos Ltd. (Edinburgh, Scotland), a developer of infrared sensors that spun out of Siemens in 2007, has raised $4 million to help it pitch for design wins in smartphones and tablet computers. The round was led by Robert Bosch Venture Capital GmbH, Seraphom Capital, Siemens Technology Accelerator and the Scottish Investment Bank. The company reckons its low-power IR technology when applied to gesture and proximity detection consumes about one-thousandth that of competing technologies. Pyreos’ passive infrared sensor technology is already in use in industrial gas and flame markets and for handheld spectroscopy in the dairy, winery and lubricant industries. The Pyreos combined gesture and proximity sensor uses microwatts of power which allows designers of portable consumer electronics to create “always on” and “wake up on motion” gesture recognition equipment. Pyreos plans to launch two products; one that recognizes proximity and gestures at 20cm range and another that performs the same combined function at one meter. Pyreos makes use of sputtered thin films of lead zirconate titanate (PZT) laid down in a crystalline orientation (111) that provides a spontaneous permanent polarization and a Curie point above 500 degrees C. The IR sensors are manufactured on a silicon membrane MEMS device as uncooled IR sensors and sensor arrays. The peak wavelength absorption is tunable so the sensors can operate from terahertz through infra-red, visible and even ultraviolet. The applications are similarly varied. Besides consumers electronics they range from spectroscopic materials analysis, through oil, gas and flame sensing, medical applications such as diabetes monitoring and breath analysis for early illness detection. Claus Schmidt, managing director of Robert Bosch Venture Capital GmbH commented: “The design breakthrough they have achieved in reducing power consumption and hence eliminating the long-standing, industry barrier of the battery drainage issue means the potential in mobile and handheld applications across consumer and industrial markets globally, is explosive. The investment will fund growth in the team to extend their established, international customer base further.” Br/N-based dopants open up the band-gap in graphene nanoplatelets for the design of FETs By Julien Happich Researchers at the Ulsan National Institute of Science and Technology (UNIST in Korea) unveiled a method for the mass production of boron/nitrogen co-doped graphene nanoplatelets, which led to the fabrication of a graphene-based field-effect transistor (FET). Led by Prof. Jong-Beom Baek, the research team uses a simple solvothermal reaction of BBr3/CCl4/N2 in the presence of potassium to mass produce boron/nitrogen co-doped graphene nanoplatelets (BCN-graphene). Since the discovery of graphene, various methods of making graphene-based field effect transistors (FETs) have been exploited, including doping graphene tailoring graphene-like a nanoribbon, and using boron nitride as a support. Among the methods of controlling the band-gap of graphene, doping methods show the most promise in terms of industrial scale feasibility. Although world leading researchers have tried to add boron into graphitic framework to open its band-gap for semiconductor applications, there has not been any notable success yet. Since the atomic size of boron (85 pm) is larger than that of carbon (77 pm), it is difficult to accommodate boron into the graphitic network structure. The new synthetic protocol has revealed that boron/nitrogen co-doping is only feasible when carbon tetrachloride (CCl4) is treated with boron tribromide (BBr3) and nitrogen (N2) gas. In order to help boron-doping into graphene structure, the research team used nitrogen (70 pm), which is a bit smaller than carbon and boron. The idea was very simple, but the result was surprising. Pairing two nitrogen atoms and two boron atoms can compensate for the atomic size mismatch. Thus, boron and nitrogen pairs can be easily introduced into the graphitic network. The resultant BCN-graphene generates a band-gap for FETs. A schematic representation for the formation of BCNgraphene via solvothermal reaction between carbon tetrachloride (CCl4) boron tribromide (BBr3) and nitrogen (N2) in the presence of potassium (K). www.electronics-eetimes.com Electronic Engineering Times Europe January 2014 15


EETE JAN 2014
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