Time filter

Source Type

Lu P.H.D.,University of New South Wales | Strutzberg H.,CiS Research Institute for Micro Sensors and Photovoltaics | Wenham S.,University of New South Wales | Lennon A.,University of New South Wales
Electrochimica Acta | Year: 2014

Hydrogen can act to reduce recombination at silicon surfaces for solar cell devices and consequently the ability of dielectric layers to provide a source of hydrogen for this purpose is of interest. However, due to the ubiquitous nature of hydrogen and its mobility, direct measurements of hydrogen incorporation in dielectric layers are challenging. In this paper, we report the use of secondary ion mass spectrometry measurements to show that deuterium from an electrolyte can be incorporated in an anodic aluminium oxide (AAO) layer and be introduced into an underlying amorphous silicon layer during anodisation of aluminium on silicon wafers. After annealing at 400 °C, the concentration of deuterium in the AAO was reduced by a factor of two, as the deuterium was re-distributed to the interface between the amorphous silicon and AAO and to the amorphous silicon. The assumption that hydrogen, from an aqueous electrolyte, could be similarly incorporated in AAO, is supported by the observation that the hydrogen content in the underlying amorphous silicon was increased by a factor of ∼ 3 after anodisation. Evidence for hydrogen being introduced into crystalline silicon after aluminium anodisation was provided by electrochemical capacitance voltage measurements indicating boron electrical deactivation in the underlying crystalline silicon. If introduced hydrogen can electrically deactivate dopant atoms at the surface, then it is reasonable to assume that it could also deactivate recombination-active states at the crystalline silicon interface therefore enabling higher minority carrier lifetimes in the silicon wafer. © 2014 Elsevier Ltd.

Takeuchi N.,Yokohama National University | Ortlepp T.,CiS Research Institute for Micro Sensors and Photovoltaics | Yamanashi Y.,Yokohama National University | Yoshikawa N.,Yokohama National University
IEEE Transactions on Applied Superconductivity | Year: 2014

We experimentally demonstrated high-speed logic operations of adiabatic quantum-flux-parametron (AQFP) gates through the use of quantum-flux-latches (QFLs). In QFL-based high-speed test circuits (QHTCs), the output data of the circuits under test (CUTs), which are driven by high-speed excitation currents, are stored in QFLs and are slowly read out using low-speed excitation currents. We designed and fabricated three types of QHTCs using QFLs with different circuit parameters, where the CUTs were buffer gates and and gates. We confirmed the correct operation of buffer gates and and gates at 1 GHz. The obtained bias margins of the 1 GHz excitation currents were more than ± 30$% for each QHTC, which is wide enough for high-speed logic operations of AQFP gates. © 2002-2011 IEEE.

Takeuchi N.,Yokohama National University | Ortlepp T.,CiS Research Institute for Micro Sensors and Photovoltaics | Yamanashi Y.,Yokohama National University | Yoshikawa N.,Yokohama National University
Journal of Applied Physics | Year: 2014

We herein propose the quantum-flux-latch (QFL) as a novel latch for adiabatic quantum-flux-parametron (AQFP) logic. A QFL is very compact and compatible with AQFP logic gates and can be read out in one clock cycle. Simulation results revealed that the QFL operates at 5 GHz with wide parameter margins of more than ±22%. The calculated energy dissipation was only ∼0.1 aJ/bit, which yields a small energy delay product of 20 aJ·ps. We also designed shift registers using QFLs to demonstrate more complex circuits with QFLs. Finally, we experimentally demonstrated correct operations of the QFL and a 1-bit shift register (a D flip-flop). © 2014 AIP Publishing LLC.

Romanyuk O.,ASCR Institute of Physics Prague | Hannappel T.,TU Ilmenau | Hannappel T.,CiS Research Institute for Micro Sensors and Photovoltaics | Grosse F.,Paul Drude Institute for Solid State Electronics
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The atomic structure of GaP(111)/Si(111), GaP(110)/Si(110), and GaP(113)/Si(113) heterointerfaces was studied by ab initio calculations employing the density functional theory (DFT). Relative formation energies were computed for the interface layers allowing for atomic intermixing. The application of the electron-counting model, a construction principle used for surface reconstructions, to the case of the GaP(111)/Si(111) interfaces leads to electronic compensation at the heterovalent interfaces and to a reduction of the interface formation energy. The specific equilibrium (111) interface reconstruction can be tuned by changing the chemical potential. In particular, the GaP(111)A/Si(111) interface was found to be abrupt and uncompensated under P-rich conditions, whereas it is compensated under Ga-rich conditions. The GaP(111)B/Si(111) interface was found to be compensated. Contrary to the (111) interfaces, stoichiometric abrupt interfaces were found to be the most energetically favorable for the GaP(110)/Si(110) and the GaP(113)/Si(113) interfaces. These interfaces do not reconstruct. Although both interfaces are compensated, the GaP(113)/Si(113) superlattice exhibits a polarization field, in contrast to the (110) superlattice. © 2013 American Physical Society.

Agency: Cordis | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-2011-ITN | Award Amount: 4.52M | Year: 2012

TALENT is a 4-year multi-site training network aiming at career development of young researchers on design, construction, manufacturing, testing and commissioning of innovative radiation hard detector modules and novel scientific instruments. TALENT provides, to 15 ESRs and 2 ERs, training for deep understanding of the complexity of scientific instrument building from theoretical design until industrial manufacturing cost efficiency considerations. The network consists of 9 academic institutions and 8 industrial companies of excellence, providing the researchers a multicultural, truly stimulating and interdisciplinary learning environment. The 2006 report of ESFRI and the European Strategy for Particle Physics set the CERN Large Hadron Collider (LHC) Upgrade and enhancement of intersectoral R&D as priorities to keep the leading high energy physics facilities and expertise of Europe at the world-class level. TALENT will make substantial advancements into these objectives. The research program significantly contributes into CERN ATLAS R&D project, the Insertable B-layer (IBL). Furthermore, IBLs innovative detector modules and instrumentation are already showing major potential for industrial applications in satellite instruments, X-ray systems, sensor technologies, medical imaging and cancer therapy. To enhance intersectoral R&D and training collaboration as well as mutual knowledge transfer, and thus to speed up the development of the IBL technologies, major R&D efforts within TALENT are put into these industrial applications. The mutual R&D interests the intersectoral consortium partners share is likely to lead into particularly creative multidisciplinary learning environment within TALENT. The chosen training approach will deepen the existing R&D collaborations between the partners and, more importantly, give the participating young researchers expertise and understanding to build a successful international career in R&D in science, industry or in their interface.

Discover hidden collaborations