http://www.sciencearchived.com Science News, Articles and Vacancies Fri, 12 Mar 2010 12:12:27 +0000 http://backend.userland.com/rss092 en A III-nitride-based photogated transistor using photons to control the channel width of an otherwise gateless field effect transistor (FET) is investigated. This is accomplished by stacking sequential layers of p-GaN/InGaN/n-GaN on a Si substrate in an array of nanorods. The nitride p-i-n diode can ... [Appl. Phys. Lett. 96, 101114 (2010)] published Thu Mar 11, 2010.]]> http://www.sciencearchived.com/photogated-transistor-of-iii-nitride-nanorods/ In this letter, we show theoretically how the light-confining properties of triply-resonant photonic resonators can be tailored to enable dramatic enhancements of the conversion efficiency of terahertz (THz) generation via nonlinear frequency down-conversion processes. Using detailed numerical calcu ... [Appl. Phys. Lett. 96, 101110 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/efficient-low-power-terahertz-generation-via-on-chip-triply-resonant-nonlinear-frequency-mixing/ We demonstrate metamaterials at the mid-infrared (mid-IR) wavelengths (812 [mu]m) that can be widely tuned by doping in adjacent semiconductor epilayers. The metamaterials are based on metallic split ring resonators (SRRs) fabricated on doped indium antimonide (InSb). Finite integral time-domain si ... [Appl. Phys. Lett. 96, 101111 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/doping-tunable-resonance-toward-electrically-tunable-mid-infrared-metamaterials/ Schottky photodiodes based on Au-ZnMgO/sapphire are demonstrated covering the spectral region from 3.35 to 3.48 eV, with UV/VIS rejection ratios up to ~10 and responsivities as high as 185 A/W. Both the rejection ratio and the responsivity are shown to be largely enhanced by the presence of an inter ... [Appl. Phys. Lett. 96, 101112 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/high-responsivity-and-internal-gain-mechanisms-in-au-znmgo-schottky-photodiodes/ We present a tuneable optical waveguide using dielectrophoretically controlled nanoparticles in microfluidics. Silicon dioxide nanoparticles of different sizes in de-ionized water are channelled through a microfluidic system. An array of microelectrodes generates the dielectrophoretic force to funne ... [Appl. Phys. Lett. 96, 101108 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/dielectrophoretically-tuneable-optical-waveguides-using-nanoparticles-in-microfluidics/ Electronic, optical, and electrical properties of CdZnO/MgZnO quantum well (QW) structures, considering internal field and polarization effect, are investigated by using many-body theory. The CdZnO/MgZnO QW structure with higher Cd composition, which has deeper and stronger confinement, is found to ... [Appl. Phys. Lett. 96, 101113 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/electronic-and-optical-properties-of-cdzno-quantum-well-structures-with-electric-field-and-polarization-effects/ A high-speed multiwavelength quantum dot comb laser, grown by molecular beam epitaxy, is demonstrated. The device is characterized with a 75.9 nm (full width at half maximum) and a 91.4 nm (Delta) wide lasing spectrum. There are 105 and 185 simultaneously emitted longitudinal modes with a maximum ch ... [Appl. Phys. Lett. 96, 101107 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/high-performance-tunnel-injection-quantum-dot-comb-laser/ A zero index metamaterial (ZIM) can be utilized to block wave (super-reflection) or conceal objects completely (cloaking). The super-reflection device can be realized by a Mu zero (Epsilon zero) metamaterial with a perfect electric (magnetic) conductor inclusion of arbitrary shape and size for a tra ... [Appl. Phys. Lett. 96, 101109 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/super-reflection-and-cloaking-based-on-zero-index-metamaterial/ We report the demonstration of phase-locked arrays of surface-emitting distributed-feedback (DFB) terahertz quantum-cascade lasers with single-mode operations. Carefully designed phase sector locks several surface-emitting DFB laser ridges in-phase, creating tighter beam-patterns along the phased-ar ... [Appl. Phys. Lett. 96, 101106 (2010)] published Wed Mar 10, 2010.]]> http://www.sciencearchived.com/phase-locked-arrays-of-surface-emitting-terahertz-quantum-cascade-lasers/ http://www.sciencearchived.com/celestron-celebrates-its-golden-anniversary/