Electrical characteristics of amorphous iron-tungsten contacts on silicon

The electrical characteristics of amorphous Fe-W contacts have been determined on both p-type and n-type silicon. The amorphous films were obtained by cosputtering from a composite target. Contact resistivities, pc=1×10^−7 and pc=2.8×10^−6, were measured on n+ and p+ silicon, respectively. These values remain constant after thermal treatment up to at least 500°C. A barrier height, φBn=0.61 V, was measured on n-type silicon

Substrate orientation dependence of enhanced epitaxial regrowth of silicon

This work extends the study of dopant-enhanced epitaxial regrowth rate of amorphized Si from the to the and orientations of Si. Boron and phosphorus dopants are considered. The annealing temperatures are 500 and 550 °C. Phosphorus enhances the growth rates in all three orientations by a constant factor of 8.1±0.9. Boron produces a higher enhancement factor of 12.2±1.2, except in the case of . Implications of the results on various growth models are considered. The crystalline quality of regrown layers is improved in the doped samples

POV-näyttö puhaltimen moottorilla

Tiivistelmä. Persistence of Vision (POV) on ihmissilmään liittyvä konsepti, jonka mukaan ihminen näkee kaikkialla jälkikuvia. Ikään kuin kaikki nähtäisiin pitkällä valotusajalla otettuina kuvina. Tähän ilmiöön liittyen on keksitty tehdä nopeasti pyöriviä LED-POV-näyttöjä, joissa yksi rivi LED-valoja pyörii tasossa niin nopeaa, että niillä voidaan muodostaa selviä kuvia. Tässä työssä tehtiin samaan ideaan pohjautuen osoitin puhaltimesta. Puhaltimen siipeen on piirretty valkoinen viiva, jota väläytetään LED-valolla. Puhaltimen takometrista saadaan sisääntulosignaali, josta koodataan signaali LED:n väläyttämiseksi. Työssä käytettiin Arduino Uno -mikrokontrolleria. Arduinolle kirjoitettiin koodi, jolla osoitin saatiin näkymään joka kierros halutussa kulmassa. Kulma annettiin näppäimistöllä sarjaportin kautta. POV-näyttö koottiin koekytkentälevylle ja sen kierrosaika oli noin 11 ms, joka vastaa 90 Hz virkistystaajuutta.POV-display with a fan. Abstract. Persistence of Vision (POV) is a concept regarding a human eye which states that human eye sees afterimages all the time, as if we see everything as long exposure time photographs. This phenomenon has been used to make rapidly rotating platforms which create clear images with just a single row of LEDs. Based on POV phenomenon a pointer was made of a fan in this thesis. A white stripe is drawn on a propeller of a fan and it is flashed with a LED. The fan has a built-in tachometer which is used as a position encoder. A code was written to Arduino Uno microcontroller for timing the flashing of the LED. The angle where the stripe is seen is given with a keyboard through Arduino’s serial port. The POV-screen was assembled on a breadboard and its time per revolution was 11 ms which means 90 Hz refresh rate

Reaction of amorphous Ni-W and Ni-N-W films with substrate silicon

Amorphous films of Ni-W and Ni-N-W were deposited on single-crystal silicon with discharge gases of Ar or Ar+N2 by rf cosputtering of Ni and W. The reaction of these Ni-W and Ni-N-W films with the Si substrate were studied in the temperature range of 450–750 °C by a combination of backscattering spectrometry, x-ray diffraction, cross-sectional transmission electron microscopy, and resistivity measurements. Films with composition Ni36W64 are stable below 500 °C. NiSi and NiSi2 form at 500 °C, and WSi2 forms rapidly in the temperature range of 625–650 °C. The nickel silicide forms adjacent to and within the silicon, while the outer layer becomes a mixture of WSi2 and NiSi2. The morphologies of the reacted layers are revealed by cross-sectional transmission electron microscopy. The crystallization temperature of amorphous Ni36W64 films on SiO2 is near 650 °C also. Adding nitrogen to form amorphous Ni30N21W49 films lowers the crystallization temperature, but raises the reaction temperature with Si to 750 °C

"Earth observation for land-atmosphere interaction science", Preface

Non peer reviewe

Charge-coupled devices with fast timing for astrophysics and space physics research

A charge coupled device is under development with fast timing capability (15 millisecond full frame readout, 30 microsecond resolution for measuring the time of individual pixel hits). The fast timing CCD will be used in conjunction with a CsI microfiber array or segmented scintillator matrix detector to detect x rays and gamma rays with submillimeter position resolution. The initial application will be in conjunction with a coded aperture hard x ray/gamma ray astronomy instrument. We describe the concept and the readout architecture of the device

Foliage surface ozone deposition : a role for surface moisture?

Peer reviewe

Superconducting microstrip detectors

Superconducting NbN microstrip counters feature radiation hardness two orders of magnitude higher than conventional Si strip detectors, spatial resolution limited only by lithographic techniques (0.1 - 2 microns), intrinsic signal rise time of 2 ps, and signal transport over large distances without losses. The aim of this proposal is to improve understanding of the physics of such detectors and to establish their large- scale feasibility