1,685 research outputs found

    Growth of Nitrogen-Doped Mg~xZn~1~-~xO for Use in Visible Rejection Photodetectors

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    Improvement in the Schottky behavior of metal (Au) contacts with Mg0.01Zn0.99O and Mg0.01Zn0.99O:N thin films were observed by treating the films with hydrogen peroxide (H2O2) (dipping of samples in H2O2 at 100 _C for 3 min). Contacts formed on untreated film showed Ohmic behavior in the current-voltage (I-V ) measurements. The H2O2 treatment led to a smooth surface morphology for the films and resulted in Schottky contact of Au fabricated on the treated films with barrier heights of 0.82≈0.85 eV. The absolute current density at a reverse bias of 3 V was 1≈6 × 10−6 A/cm2 for Au contacts on H2O2-treated films. The treated films showed lower electron concentration than the untreated films due to removal of the relatively high conducting top layers of the thin films. A metal-semiconductor-metal (MSM) detector was fabricated using a Mg0.05Zn0.95O:N film and was characterized for its spectral response

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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