A chip-size spectrometer is realized by combining a linear variable band-pass filter with a CMOS camera. The filter converts the spectral information of the incident light into a spatially dependent signal that is analyzed by the camera. A fluidic platform is integrated onto the spectrometer for analyzing the fluorescence from moving objects. The target is continuously excited within an anti-resonant waveguide, and its fluorescence spectrum is recorded as the object traverses the detection area.

Improved p-type conductivity is demonstrated in AlGaN:Mg superlattice (SL) cladding layers with average Al composition $60%. The vertical conductivity ranges from 6.6 Â 10 À5 S/cm at a DC current of 1 mA to $0.1 S/cm at 550 mA and approaches the lateral conductivity that was obtained from Hall-effect measurements. The effective acceptor activation energy (E A) in the SL was determined to be 17 meV, nearly 10Â smaller than E A in homogeneous p-GaN. The devices sustain current densities of 11 kA/cm 2 under DC and up to 21 kA/cm 2 under pulsed operation. V

Fabrication of nanoscale, high throughput, high aspect ratio freestanding gratings J. Vac. Sci. Technol. B 30, 06FF03 (2012); 10.1116/1.4755815 Influence of catalytic gold and silver metal nanoparticles on structural, optical, and vibrational properties of silicon nanowires synthesized by metal-assisted chemical etching J. Appl. Phys. 112, 073509 (2012); 10.1063/1.4757009 Fabrication of vertically aligned Si nanowires on Si (100) substrates utilizing metal-assisted etching J. Vac. Sci. Technol. A 28, 735 (2010); 10.1116/1.3336572In-plane control of morphology and tunable photoluminescence in porous silicon produced by metal-assisted electroless chemical etching High aspect ratio nanoscale features are becoming increasingly important in a wide range of applications. In this paper, the authors describe the concepts of vertical directionality-controlled metal-assisted chemical etching (V-MaCE) and demonstrate resolution and fabrication capabilities for V-MaCE in the context of x-ray diffractive optics. The authors fabricate x-ray grating structures having a period of 50 nm, 25 nm lines, and 25 nm spaces, with a thickness of 1.26 lm, and achieve an aspect ratio of $50:1. In order to maintain the vertical etching profiles of these deep structures, the authors demonstrate the design and usage of adjacent, outrigger, gratings to balance the electron-hole concentration.

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