With a simple coating, nanowires show dramatic increase in efficiency, sensitivity

first_img Read Full Story By applying a coating to individual silicon nanowires, researchers at Harvard and Berkeley have significantly improved the materials’ efficiency and sensitivity.The findings, published in the May 20, 2011, issue of Nano Letters, suggest that the coated wires hold promise for photodetectors and energy harvesting technologies like solar cells.Due to a large surface-to-volume ratio, nanowires typically suffer from a high surface recombination rate, meaning that photogenerated charges recombine rather than being collected at the terminals. The carrier lifetime of a basic nanowire is shortened by four to five orders of magnitude, reducing the material’s efficiency in applications like solar cells to a few percent.“Nanowires have the potential to offer high energy conversion at low cost, yet their limited efficiency has held them back,” says Kenneth Crozier, associate professor of electrical engineering at the Harvard School of Engineering and Applied Sciences (SEAS).With their latest work, Crozier and his colleagues demonstrated what could be a promising solution. Making fine-precision measurements on single nanowires coated with an amorphous silicon layer, the team showed a dramatic reduction in the surface recombination.Co-author Yaping Dan, a postdoctoral fellow in Crozier’s lab who spearheaded the experiments, suggests that the reason for the increased efficiency is that the coating physically extends the broken atom bonds at the single-crystalline silicon surface. At the same time, the coating also may form a high–electric potential barrier at the interface, which confines the photogenerated charge carriers inside the single-crystalline silicon.last_img read more

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Peruvian Air Force Develops High-Tech Air Surveillance Radar

first_img With the objective of improving airspace surveillance capabilities over the Peruvian Amazon, Peruvian Air Force (FAP) technical personnel are in the midst of developing the prototype of a high-tech air surveillance radar that will be ready to be put into operational service at the end of this year. The development project is the product of an agreement between the National Commission for Development and Life without Drugs (DEVIDA) and the FAP, through which DEVIDA facilitates financial resources for strengthening the national air surveillance system. The agreement was signed by the chair of DEVIDA, Carmen Masías Claux, and the FAP’s commander of operations, Lieutenant General Carlos Bohórquez Castellares, and forms part of DEVIDA’s effort to coordinate with state agencies involved in the fight against drug trafficking. Masías called attention to the special deployment carried out in the airspace near the border with Brazil, a country with which joint efforts are being conducted in this regard and that is expected to be the primary area of interest for the deployment of the radars developed by the FAP. Although scant information is available, the FAP’s Electronics Service (SELEC) is believed to be in charge of the project to develop the radar, which is expected to have 3D capabilities – ideal for air surveillance tasks – enabling efficient three-dimensional radar coverage by capturing data on the elevation, range, and azimuth of the targets detected in the radar system’s area of influence. By Dialogo July 13, 2012last_img read more

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JTF-Bravo Supports Rescue Operations in Panama after the Devastation of Eta

first_imgBy Roberto López Dubois/Diálogo November 09, 2020 Hurricane Eta hit the Central American region, where torrential rains have caused flooding and landslides. Although the storm didn’t pass directly over Panama, it left dozens of people dead and missing.To support the search, rescue, and evacuation efforts of the government of Panama, U.S. Southern Command, through Joint Task Force Bravo (JTF-Bravo, deployed a team of 42 service members and three helicopters, one HH-60 Black Hawk and two CH-47 Chinook. The JTF-Bravo team joined the Panamanian government’s Operation Homeland (Operación Patria) to respond to the critical situation in the provinces of Chiriquí, Veraguas, and Coclé, coordinating efforts with Panama’s National Civil Protection System (SINAPROC, in Spanish) and the Panamanian Air and Naval Service (SENAN, in Spanish).JTF-Bravo has also been providing support to the Comarca Ngabe-Buglé, the largest indigenous territory in the country with a mountainous topography that is difficult to access.“The @senanpanama together with the @jtfbravo of U.S. Southern Command, brought water and 385 bags of food as humanitarian aid to the families affected by the floods in the communities of Boca de Remedios and Junta Maní [Comarca Ngabe-Buglé],” the Presidency of Panama said on Twitter on November 7.Commissioner Edson Castillo, SENAN director of Operations, highlighted JTF-Bravo’s rescue operation of an entire Family in the province of Chiriquí. “The Warrior 70, a Chinook, which is part of the contingent of aircraft that JTF-Bravo sent to Panama, carried out the rescue of eight members of a family on November 7, who were isolated as a result of the landslides and the obstruction of the road leading to the district of Tierras Altas,” said Commissioner Castillo to Diálogo.Another support mission of JTF-Bravo is to help SINAPROC move emergency personnel to critical locations to respond to life-threatening conditions.At a press conference on November 7, Panamanian Minister of Public Security Juan Pino said that 2,587 people have been affected by the hurricane and that 832 people have been rescued. He added that there were about 25 landslides.“Thanks to the @jtfbravo of U.S. Southern Command for allocating three helicopters and a U.S. team of 42 people to redouble efforts in the search, rescue, and evacuation of our affected brothers and sisters. Solidarity among countries for the well-being of our people!” said Panamanian President Laurentino Cortizo on Twitter.For his part, Commissioner Castillo highlighted the combined work between SENAND and JTF-Bravo, which he described as “extraordinary.”“The bilateral relationship between both nations has always made clear the support and brotherhood that characterize us,” he added.last_img read more

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