A novel antenna effect is demonstrated in arrays of 500, 200 and 100 silicon nanowires embedded in silicon dioxide. The gratings are analyzed using spectral and polarisation resolved photocurrent microscopy. Resonant enhancements in the electric field and photocurrent response are observed at multiple wavelengths corresponding to coupling of incident radiation into the grating's multiple-scattering electromagnetic modes. The photoresponse retains the sinusoidal polarisation anisotropy expected in single nanowires. The resonances are modeled using electromagnetic scattering theory and show excellent agreement with measurement. An experimental quality factor of Q=10 was measured for the gratings, exceeding that of a single wire, but lower than expected from theory. The difference is ascribed to the finite length of the wires and their termination at ohmic contacts. Strategies to improve Q are discussed, and a grating is presented to resonantly enhance light detection at red, green and blue wavelengths for application as a colour imaging sensor.

Silicon-based lighting show promise for display and solid state lighting use. Here we demonstrate a novel thin film light emitting diode device using nanocrystalline silicon quantum dots as an emission layer, and metal oxides as charge transport layers. Sputtering deposition conditions for the nickel and zinc oxides were explored in order to balance deposition rate with minimal roughness, optical absorption, and electrical resistivity. Devices displaying characteristic diode current-voltage behavior were routinely produced, although most showed significant reverse saturation current due to the presence of shunts. Current-voltage behavior of devices made in the same batch showed high repeatability, however variations in device performance was observed between batches while the parameters of synthesis were kept constant. Some devices were observed to emit orange-colored light, consistent with photoluminescence behavior of the silicon quantum dots. Photomultiplier tube measurements shows a turn-on voltage of 5V and an exponential increase in light emission with voltage increase.

A novel antenna effect is demonstrated in arrays of 500, 200 and 100 silicon nanowires embedded in silicon dioxide. The gratings are analyzed using spectral and polarisation resolved photocurrent microscopy. Resonant enhancements in the electric field and photocurrent response are observed at multiple wavelengths corresponding to coupling of incident radiation into the grating's multiple-scattering electromagnetic modes. The photoresponse retains the sinusoidal polarisation anisotropy expected in single nanowires. The resonances are modeled using electromagnetic scattering theory and show excellent agreement with measurement. An experimental quality factor of Q=10 was measured for the gratings, exceeding that of a single wire, but lower than expected from theory. The difference is ascribed to the finite length of the wires and their termination at ohmic contacts. Strategies to improve Q are discussed, and a grating is presented to resonantly enhance light detection at red, green and blue wavelengths for application as a colour imaging sensor.

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