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Plasmonic and nanophotonic structures enable the manipulation and molding of light in nanoscale devices. These nanostructures are designed and integrated to achieve broadband photocurrent enhancement in ultrathin film photovoltaics.
We propose a planar ultra-thin absorber concept exploiting plasmonic resonance absorption enhancement. We calculate >13-fold enhancement in a 7.5 nm thin-film absorber yielding a maximum absorption of 74.4%. Broadband and wide-angle absorption is demonstrated.
III–V semiconductors like GaAs and InGaN are very promising candidates for solar cells. While GaAs has near-ideal bandgap to reach the maximum possible efficiency limit for single junction solar cells, InGaN provides the ability to tune the bandgap of absorbing layers over a wide energy range. Since III–V semiconductors are mostly direct bandgap semiconductors, they are also very strong absorbers...
We analytically determine the contribution of plasmonic nanospheres embedded in absorbing media to total optical absorption. We estimate gains of ∼30% for a 1 µm µc-Si solar cell using 54 nm silica-coated silver nanoparticles.
We present our design and characterization on SPADs and NFADs with InGaAs/GaAsSb Type II SL absorber regions on InP substrates with extended wavelength detection up to 2.4µm wavelengths for single photon counting applications. Packaged devices showed very low variation at −40oC, with ∼100nA dark current at 2 volts below breakdown voltage. The measured DCR was 106 Hz at 2 volts excess bias at 223K.
Photonic crystals are widely known for their light-trapping capabilities. This is often associated with the occurrence of a photonic band gap or other suppression in the electromagnetic density of states. This also enables unprecedented forms of strong-coupling between light and matter. A less studied form of light-trapping occurs in the higher bands of a photonic crystal, where the electromagnetic...
The addition of a tiny amount of Aluminum nanoparticles in dye solutions is shown to yield a significant enhancement of the down conversion of ultraviolet light while maintaining a high transparency at visible wavelengths.
In conclusion we have evaluated the potential of In(Ga)As quantum dots grown on silicon as photodiodes by characterising their electrical and optical properties. The responsivity spectra showed a peak related to quantum dot transition at 1280 nm of 5 mA/W, with an absorption tail extending beyond 1.3 µm. The measured dark currents are over three orders of magnitude lower than those for Ge on Si detectors...
We demonstrate that periodic metallic gratings can greatly enhance the optical absorption efficiency of thin-film solar cells. We also introduce aperiodic multilayer structures with highly directional absorptivity for both polarizations for solar thermophotovoltaic systems.
In the subwavelength regime, the optimal surface texture for light trapping in solar cells remains to be found. We use computational inverse electromagnetic design to find the optimal nanoscale surface texture.
Plasmonic nanostructures can increase photon capture and lead to enhancement of photocurrent in photovoltaic (PV) cells. This has special implications for Si absorber layers much thinner than 10 µm, when optical absorption of near-bandgap light is reduced and current light trapping schemes, such as surface texturing, may be a poor candidate. There has been an increasing amount of work in the field...
In recent years a great amount of research has been focused on metamaterials, initially for fabrication of left-handed materials for use in devices such as superlenses or electromagnetic cloaking. Such devices have been developed and demonstrated in regimes from the radio frequency all the way to infrared and near optical frequencies. More recently, it has been shown that by careful adjustment of...
A photodetector comprised of a colloidal germanium nanoparticle active material is reported. The non-toxic, heavy-metal free germanium nanoparticles are synthesized from solution and reap the benefits of solution-processing.
We theoretically incorporate quantum coherent absorption in an actively modelocked quantum cascade laser. The laser self-starts from initial quantum noise and produces a stable train of modelocked pulses at high pump powers.
Large area and semi-transparent highly light sensitive nanocrystal skin is demonstrated via spray-coating nanocrystals on top of polyelectrolyte-polymers based on photogenerated potential buildup where no external bias is applied.
Terahertz waves (0.1–10 THz) have promising applications in several fields including spectroscopy, imaging, and wireless communication [1]. However, several components still need to be developed for THz waves: a source, detector, filter, absorber, and modulator. In fact, an effective method for controlling THz waves has not been established yet.
While saturable absorber can control the hysteresis window width in multi-mode-interferometer bi-stable laser diodes, spatial gain overlap showed significant effect on the threshold currents of the hysteresis window.
Nanolasers made from III–V active materials and metal-clad cavities have attracted research interest because of the small volume possible with metal nanocavities.1 Proposed applications include intrachip optical interconnects and optical sensors. The metal-clad nanocavities are one of several cavity approaches being studied, and differ from dielectric and semiconductor nanocavities in their high optical...
Single isolated attosecond pulse is a new powerful tool for studying dynamics of correlated electron motion in pump-probe experiments [1]. Such pulses, as short as 67 attoseconds, can now be generated with the Double Optical Gating (DOG) method. The broadband XUV supercontinuum spectrum of the isolated attosecond pulse is particularly suitable for probing the time variation of the electronic states...
We demonstrate the p-doping influence on number of dots explained by comparison with structures has different quantity of material deposited. Peak modal gain at high temperatures is higher in p-doped structure compare to undoped one.
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