Podcast: Sportsday on talkSPORT 2, July 25

first_imgThis Monday morning on Sportsday we looked back on day three of the second Test between England and Pakistan at Old Trafford, England opened up a 489-run lead over Pakistan after choosing not to enforce the follow-on.We have all the reaction from the Tour de France as Chris Froome became Britain’s first three-time winner when he crossed the finish line of the 21-stage race in Paris yesterday.We also look back on the Hungarian Grand Prix, Super League and how The World Anti-Doping Agency (Wada) is “disappointed” its recommendation to ban Russia from next month’s Olympic Games in Rio has been rejected.All brought to you by Jake Robson and the team.last_img

Baseball World Series MVP Award Named for Willie Mays

Willie Mays (AP Photo/Bebeto Matthews, File)NEW YORK (AP) — Major League Baseball has named its World Series Most Valuable Player award after Willie Mays.The decision was announced Friday, the 63rd anniversary of Mays’ back-to-the-plate catch in deep center field at the Polo Grounds for the New York Giants against Cleveland’s Vic Wertz in the World Series opener. The Giants went on to sweep the Indians.The Series MVP award began the following year when it was won by Brooklyn Dodgers pitcher Johnny Podres.San Francisco Giants’ Willie Mays is all set for a workout at the baseball club’s training camp at Casa Grande,  (AP Photo/RDS)Now 86, Mays played in 24 All-Star Games during a 22-year-career with the New York and San Francisco Giants, and the New York Mets.

Lightemitting transistor uses light to transfer an electrical signal

first_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. At left, the drawing of the LET describes the scientists’ observation, shown in the electroluminescence intensity map at right. The infrared light emitted from the LET reaches the detector, meaning that an electrical signal can be transferred to the detector by light. Credit: Shin-ichi Saito, et al. In one of the early discoveries of the current “silicon electrophotonics era,” scientists from Hitachi, Ltd. in Tokyo have built a light-emitting transistor (LET) that transfers, detects and controls an electrical signal all on a single nanometer-sized chip. Using a silicon-on-insulator (SOI) substrate, the group could optically connect the LET to a detector, resulting in a tiny chip that may integrate a wide range of microelectronics and photonics nano devices. Citation: Light-emitting transistor uses light to transfer an electrical signal (2006, November 1) retrieved 18 August 2019 from https://phys.org/news/2006-11-light-emitting-transistor-electrical.html “With LETs, we could develop an optical interconnection beyond the present copper interconnection,” Shin-Ichi Saito, co-author of the study in Applied Physics Letters, told PhysOrg.com. “If LETs are really integrated on silicon chips, we might reduce power dissipation (since light does not have electrical resistance), as well as RC [Resistive Capacitive] delay: in electrical circuits, the interlayer coupling capacitance reduces the speed of electrical signals, while such a delay might be reduced in optical interconnections.”Similar to a standard field-effect transistor, Saito et al.’s LET takes advantage of some interesting properties of 2D electron and electron hole systems, called “quantum confinement effects.” By reducing the thickness of the crystal silicon down to the nanometer scale, the scientists fabricated an ultra-thin single crystal silicon film, directly connected to the thick silicon electrodes. In such a design, n-type (electrons) and p-type (holes) semiconductors lie next to each other separated by a narrow junction. As the electrons and holes efficiently eliminate each other in a process called “recombination,” photons are emitted; thus electrical signals can be converted to optical signals. This close-up drawing of the LET shows the ultrathin silicon junction acting as a quantum well. After recombination, the electric carriers are confined into a standing wave, greatly increasing the electroluminescence efficiency. Credit: Shin-ichi Saito, et al.center_img Explore further “The key idea is that the 2D conduction band electrons behave just like electrons in direct band-gap semiconductors,” said Saito. “In bulk Si, the conduction band electrons move very fast with a large momentum. However, in the ultra-thin Si, the electrons cannot move perpendicular to the substrate with such a large momentum, simply because that direction is restricted. Many people also consider that this quantum mechanical confinement plays some role for the enhanced luminescence in nano-scale silicon.”To optically interconnect this electrical signal from the LET to a detector–which were electrically isolated but on the same silicon chip–the group applied a forward voltage bias to the LET. The scientists observed the light from the LET to reach the photodetector, and measured the “photocurrent” in the detector to increase with a voltage increase, and decrease when the voltage was turned off (detector limitations caused some current to continue flowing).Although the Hitachi group points out limitations to the present experimental set-up that need to be fixed before applying the principle to marketable technology, they suggest solutions for these problems: for example, reducing the response time of the detector and using waveguides to contain the light on the chip. However, the achievement shows how, using curious phenomena of quantum mechanics, photons, just like electrons, can be manipulated on a silicon chip. Quite possibly, future integrated circuits may use lights instead of currents to enhance performance while reducing power dissipation.“We have just confirmed the basic operation principle for this LET,” said Saito. “The hope is that this is just the beginning of more research; we have lots to do.”Citation: Saito, Shin-ichi, Hisamoto, Digh, Shimizu, Haruka, Hamamura, Hirotaka, Tsuchiya, Ryuta, Matsui, Yuichi, Mine, Toshiyuki, Arai, Tadashi, Sugii, Nobuyuki, Torii, Kazuyoshi, Kimura, Shin’ichiro, and Onai, Takahiro. “Silicon light-emitting transistor for on-chip optical interconnection.” Applied Physics Letters 89, 163504 (2006).By Lisa Zyga, Copyright 2006 PhysOrg.com “With the lateral carrier injections that we used, we can efficiently inject both electrons and holes directly in the quantum confined silicon,” said Saito. “Usually, nano-scale silicon structures are passivated by SiO2, which has huge potential barriers for carriers. Such a limitation does not exist in our device.”In this set-up, the p-n junction consists of a light-emitting diode (LED) made of ultrathin silicon. At a 9nm thickness, the silicon acts as a quantum well, confining the electric carriers to two dimensions, which forms a standing wave consisting of an electron. This confinement serves an especially useful purpose for integrating optical components into silicon circuits, as it enhances the electroluminescence efficiency of the junction. While other LETs–from carbon nanotubes and organic models to semiconductor and nanocrystal devices–have been demonstrated, Saito et al.’s is the first in which recombination occurs along the silicon junction and takes advantage of quantum confinement’s electroluminescence. Decline of entrepreneurship blamed for Japan woeslast_img read more