Brook GLES Pi: democratising accelerator programming

Nowadays computing is heavily-based on accelerators, however, the cost of the hardware equipment prevents equal access to heterogeneous programming. In this work we present Brook GLES Pi, a port of the accelerator programming language Brook. Our solution, primarily focused on the educational platform Raspberry Pi, allows to teach, experiment and take advantage of heterogeneous programming on any low-cost embedded device featuring an OpenGL ES 2 GPU, democratising access to accelerator programming.This work has been partially supported by the Spanish Ministry of Science and Innovation under grant TIN2015-65316-P and the HiPEAC Network of Excellence.Peer ReviewedPostprint (author's final draft

Atomic layer deposition of TbF3 thin films

Lanthanide fluoride thin films have gained interest as materials for various optical applications, including electroluminescent displays and mid-IR lasers. However, the number of atomic layer deposition (ALD) processes for lanthanide fluorides has remained low. In this work, we present an ALD process for TbF3 using tris(2,2,6,6-tetramethyl-3,5-heptanedionato)terbium and TiF4 as precursors. The films were grown at 175-350 degrees C. The process yields weakly crystalline films at the lowest deposition temperature, whereas strongly crystalline, orthorhombic TbF3 films are obtained at higher temperatures. The films deposited at 275-350 degrees C are exceptionally pure, with low contents of C, O, and H, and the content of titanium is below the detection limit (Peer reviewe

Highly conductive and stable Co9S8 thin films by atomic layer deposition : from process development and film characterization to selective and epitaxial growth

Co9S8 is an interesting sulfide material with metallic conductivity that has shown promise for various energy applications. Herein, we report a new atomic layer deposition process producing crystalline, pure, and highly conductive Co9S8 thin films using CoCl2(TMEDA) (TMEDA = N,N,N ',N '-tetramethylethylenediamine) and H2S as precursors at 180-300 degrees C. The lowest resistivity of 80 mu omega cm, best uniformity, and highest growth rate are achieved at 275 degrees C. Area-selective deposition is enabled by inherent substrate-dependency of film nucleation. We show that a continuous and conductive Co9S8 film can be prepared on oxide-covered silicon without any growth on Si-H. Besides silicon, Co9S8 films can be grown on a variety of substrates. The first example of an epitaxial Co9S8 film is shown using a GaN substrate. The Co9S8 films are stable up to 750 degrees C in N-2, 400 degrees C in forming gas, and 225 degrees C in O-2 atmosphere. The reported ALD process offers a scalable and cost-effective route to high-quality Co9S8 films, which are of interest for applications ranging from electrocatalysis and rechargeable batteries to metal barrier and liner layers in microelectronics and beyond.Peer reviewe

Improving efficiency in multiple-unit combinatorial auctions: Bundling bids from multiple bidders

In multiple-unit combinatorial auctions both bidders and bid takers can benefit from support mechanisms that suggest new bids for the bidders. We present a support tool called Group Support Mechanism, which suggests bundles of bids to several bidders not among the provisional winners. It improves upon the Quantity Support Mechanism we developed earlier. The efficiency of the final allocation is better when the Group Support Mechanism is used instead of the Quantity Support Mechanism, especially in cases when the efficient allocation consists of three or more bids

Atomic Layer Deposition of Intermetallic Co3Sn2 and Ni3Sn2 Thin Films

Intermetallics form a versatile group of materials that possess unique properties ranging from superconductivity to giant magnetoresistance. The intermetallic Co-Sn and Ni-Sn compounds are promising materials for magnetic applications as well as for anodes in lithium- and sodium-ion batteries. Herein, a method is presented for the preparation of Co3Sn2 and Ni3Sn2 thin films using diamine adducts of cobalt(II) and nickel(II) chlorides, CoCl2(TMEDA) and NiCl2(TMPDA) (TMEDA = N,N,N ',N '-tetramethylethylenediamine, TMPDA = N,N,N ',N '-tetramethyl-1,3-propanediamine) combined with tributyltin hydride. The films are grown by atomic layer deposition (ALD), a technique that enables conformal film deposition with sub-nanometer thickness control. The Co3Sn2 process fulfills the typical ALD qualifications, such as self-limiting growth, excellent film uniformity, and conformal coverage of a trench structure. X-ray diffraction (XRD) shows reflections characteristic to the hexagonal Co3Sn2 phase, which confirms that the films are, indeed, intermetallic instead of being mere alloys of Co and Sn. The films are extremely pure with impurity levels each below 1.0 at.%. Ni3Sn2 films similarly exhibit the expected XRD reflections for the intermetallic phase and are of high purity. The Co3Sn2 film show magnetic hysteresis with high coercivity values exceeding 500 Oe, indicating great potential in terms of applicability of the films.Peer reviewe

Microstructure, optical and dielectric properties of cerium oxide thin films prepared by pulsed laser deposition

Cerium oxide (CeO2) thin films were deposited on Pt (111)/Ti/SiO2/Si(100) substrates using pulsed laser deposition method at different temperatures such as, 300 K, 573 K and 873 K with 3 × 10−2 mbar oxygen partial pressure. The prepared films were systematically investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and electrical measurement system. XRD analysis clearly showed improved crystallinity of CeO2 films prepared at 573 and 873 K substrate temperatures. The AFM analysis indicated the uniform distribution of the nanocrystallites and dense structure with the roughness (RMS) of ~ 2.1–3.6 nm. The PL studies of the films showed a broad peak at ~ 366–368 nm, indicating the optical bandgap of 3.37–3.38 eV. The electrical property study showed minimum leakage current density of 2.0 × 10−7 A/cm2 at 873 K, which was measured at 100 kV and this value was much lower than that of the CeO2 film deposited at 300 K. The dielectric constants are increased and dielectric loss values decreased for the films with increasing substrate temperature