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Paper transistors could make cheap, bendy electronics possible
Technology
THE US air force is seeking to develop a cluster weapon that releases a swarm of bomblets that could each pursue and destroy targets many kilometres away, New Scientist has learned. “This is a dangerous and very worrying development,” says Noel Sharkey, a specialist in the ethics of autonomous systems at the University of Sheffield in the UK. Sharkey has argued that giving a robot the power to decide when and who to attack raises serious practical and ethical questions, and says the same would apply to the proposed weapon. The US Department of Defense revealed its requirements for the weapon in an online research request. In it, the air force asked American aerospace firms to submit proposals by 24 September for a weapon that “engages multiple targets” using “guided
Cheap, flexible transistor looks good on paper
PAPER transistors could end the hunt for alternatives to silicon chips and herald the introduction of electronic devices cheap and bendy enough to use on disposable food cans. The transistors are the work of Elvira Fortunato of the New University of Lisbon in Portugal and colleagues, 26 | NewScientist | 27 September 2008
and military vehicles,” he says. Existing “smart” cluster bombs scatter bomblets equipped with lasers and infrared sensors, which allows them to identify targets such as tanks and trucks. That’s not necessarily enough to tell friend from foe, but at least their range is limited – to about 350 metres in the case of the US-made BLU-108. The proposal, however, calls for bomblets that lock back on to targets if they happen to lose track of them, meaning they might lock on to the wrong vehicle. “The distinction between military and civilian targets cannot be made by electronics: it has to be a human decision,” says Richard Moyes of Landmine Action in London. “Relying on computerised sensors to attack –Heading for soldiers or civilians– targets raises fundamental moral and legal questions.” The air force hopes the guided It’s not clear if such weapons weapons will “increase accuracy would breach the Convention on and reduce collateral damage”. Cluster Munitions due to be That will depend on the reliability signed by 109 countries in Oslo of the weapon’s decision-making in December. The CCM permits software and its sensors, although cluster weapons as long as they according to Sharkey there is no can reliably identify targets and way these “smart” submunitions deactivate or self-destruct if they will be able to distinguish between miss. The US is not signing up, combatants and civilians. “If a because it says it is building target moves into a highly weapons intelligent enough to populated area, I can’t think of render themselves harmless if they any sensors that could reliably stray off course (New Scientist, discriminate between civilian 7 June, p 25). Paul Marks ● USAF/AFP/GETTY
You thought cluster bombs were scary? Try these…
smart submunitions”. The request says the submunitions – the formal term for bomblets – should be equipped with sensors capable of locking on to targets up to 5 kilometres away, and should have enough onboard power to chase a moving target for up to 5 minutes. “These new bomblets would effectively be miniaturised air-tosurface missiles,” says Colin King, an analyst with Jane’s, a defence publisher based in the UK.
and were reported in this month’s IEEE Electron Device Letters. Fortunato and her team built the transistors by coating both sides of a sheet of ordinary paper with metal oxides. They then applied aluminium contacts onto the coated paper. The paper acts both as a flexible substrate and as an integral part of the semiconductor “sandwich” at the heart of the transistor, helping to amplify the tiny currents that pass through the transistor. “Using the interstrate is a clear advantage,” says Professor Ioannis Kymissis of the Laboratory for Unconventional Electronics at Columbia University, New York. The transistors were produced at room temperature and tested for two months without any deterioration
in performance or stability. That makes it plausible that they could be used to make disposable microelectronics such as RFID tags and smart labels cheap enough to be used for everyday applications, such as labelling and tracking stock in supermarkets. Since they’re made of
“Paper transistors were tested for two months without any deterioration” paper, they are liable to tear or become soggy if dampened, but this can be overcome by laminating the device. Researchers have long sought ways of making electronic chips that don’t need multibillion-dollar
manufacturing plants as silicon chips do. Inorganic alternatives such as germanium are at least as fiddly as silicon, so the search has focused on organic materials. But since most organic substances conduct electricity relatively poorly, the candidates so far have been too exotic. It is not surprising then that practical transistors based on cellulose fibre have been enthusiastically received. It is the main ingredient of paper and one of the most common organic materials in the world. “This may go a long way toward achieving a dream that many groups have pursued for very low-cost, flexible organic electronics,” says Dick Slusher, director of the Georgia Tech Quantum Institute in Atlanta. Saswato Das ● www.newscientist.com
THE US air force is seeking to develop a cluster weapon that releases a swarm of bomblets that could each pursue and destroy targets many kilometres away, New Scientist has learned. “This is a dangerous and very worrying development,” says Noel Sharkey, a specialist in the ethics of autonomous systems at the University of Sheffield in the UK. Sharkey has argued that giving a robot the power to decide when and who to attack raises serious practical and ethical questions, and says the same would apply to the proposed weapon. The US Department of Defense revealed its requirements for the weapon in an online research request. In it, the air force asked American aerospace firms to submit proposals by 24 September for a weapon that “engages multiple targets” using “guided
Cheap, flexible transistor looks good on paper
PAPER transistors could end the hunt for alternatives to silicon chips and herald the introduction of electronic devices cheap and bendy enough to use on disposable food cans. The transistors are the work of Elvira Fortunato of the New University of Lisbon in Portugal and colleagues, 26 | NewScientist | 27 September 2008
and military vehicles,” he says. Existing “smart” cluster bombs scatter bomblets equipped with lasers and infrared sensors, which allows them to identify targets such as tanks and trucks. That’s not necessarily enough to tell friend from foe, but at least their range is limited – to about 350 metres in the case of the US-made BLU-108. The proposal, however, calls for bomblets that lock back on to targets if they happen to lose track of them, meaning they might lock on to the wrong vehicle. “The distinction between military and civilian targets cannot be made by electronics: it has to be a human decision,” says Richard Moyes of Landmine Action in London. “Relying on computerised sensors to attack –Heading for soldiers or civilians– targets raises fundamental moral and legal questions.” The air force hopes the guided It’s not clear if such weapons weapons will “increase accuracy would breach the Convention on and reduce collateral damage”. Cluster Munitions due to be That will depend on the reliability signed by 109 countries in Oslo of the weapon’s decision-making in December. The CCM permits software and its sensors, although cluster weapons as long as they according to Sharkey there is no can reliably identify targets and way these “smart” submunitions deactivate or self-destruct if they will be able to distinguish between miss. The US is not signing up, combatants and civilians. “If a because it says it is building target moves into a highly weapons intelligent enough to populated area, I can’t think of render themselves harmless if they any sensors that could reliably stray off course (New Scientist, discriminate between civilian 7 June, p 25). Paul Marks ● USAF/AFP/GETTY
You thought cluster bombs were scary? Try these…
smart submunitions”. The request says the submunitions – the formal term for bomblets – should be equipped with sensors capable of locking on to targets up to 5 kilometres away, and should have enough onboard power to chase a moving target for up to 5 minutes. “These new bomblets would effectively be miniaturised air-tosurface missiles,” says Colin King, an analyst with Jane’s, a defence publisher based in the UK.
and were reported in this month’s IEEE Electron Device Letters. Fortunato and her team built the transistors by coating both sides of a sheet of ordinary paper with metal oxides. They then applied aluminium contacts onto the coated paper. The paper acts both as a flexible substrate and as an integral part of the semiconductor “sandwich” at the heart of the transistor, helping to amplify the tiny currents that pass through the transistor. “Using the interstrate is a clear advantage,” says Professor Ioannis Kymissis of the Laboratory for Unconventional Electronics at Columbia University, New York. The transistors were produced at room temperature and tested for two months without any deterioration
in performance or stability. That makes it plausible that they could be used to make disposable microelectronics such as RFID tags and smart labels cheap enough to be used for everyday applications, such as labelling and tracking stock in supermarkets. Since they’re made of
“Paper transistors were tested for two months without any deterioration” paper, they are liable to tear or become soggy if dampened, but this can be overcome by laminating the device. Researchers have long sought ways of making electronic chips that don’t need multibillion-dollar
manufacturing plants as silicon chips do. Inorganic alternatives such as germanium are at least as fiddly as silicon, so the search has focused on organic materials. But since most organic substances conduct electricity relatively poorly, the candidates so far have been too exotic. It is not surprising then that practical transistors based on cellulose fibre have been enthusiastically received. It is the main ingredient of paper and one of the most common organic materials in the world. “This may go a long way toward achieving a dream that many groups have pursued for very low-cost, flexible organic electronics,” says Dick Slusher, director of the Georgia Tech Quantum Institute in Atlanta. Saswato Das ● www.newscientist.com