Soybean meal (SBM), corn gluten meal (CGM), and canola protein concentrate (CPC) as alternative protein sources to fish meal (FM) were individually evaluated for growth performance at 0, 20, 30, 40, and 50% replacement with amino acid (AA) supplementation using juvenile summer flounder, Paralichthys dentatus, in an 8-wk feeding. Two-way ANOVA indicated no significant main effect for plant protein source, but a significant main effect for replacement level. Comparison of the individual treatments revealed significant differences in weight gain (WG) between the FM treatment and 50% replacement level for all protein sources, as well as between the FM treatment and 30% replacement with CPC. Replacement of FM with SBM at 40% resulted in the least cost/kg WG. In a follow-up study, a combination of SBM-CGM-CPC at 40% replacement was evaluated with and without AA, phytase (0.2%), or taurine (1%), versus FM and SBM (40% replacement of FM) with AA. The SBM-CGM-CPC diet with either AA or taurine provided a significantly better food conversion ratio and less cost/kg WG than the SBM diet, and the SBM-CGM-CPC diet with taurine provided a significantly better protein efficiency ratio than the SBM diet. On the basis of these results, more study of taurine in plant protein diets for summer flounder appears warranted.

Self-assembly of InAs nanowire arrays with highest reported aspect ratios and number density by van der Waals epitaxy on graphene is presented.

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Growth of GaSb with low threading dislocation density directly on GaAs may be possible with the strategic strain relaxation of interfacial misfit arrays. This creates an opportunity for a multijunction solar cell with access to a wide range of well-developed direct bandgap materials. Multijunction cells with a single layer of GaSb/GaAs interfacial misfit arrays could achieve higher efficiency than state-of-the-art inverted metamorphic multi-junction cells while forgoing the need for costly compositionally graded buffer layers. To develop this technology, GaSb single junction cells were grown via molecular beam epitaxy on both GaSb and GaAs substrates to compare homoepitaxial and heteroepitaxial GaSb device results. The GaSb-on-GaSb cell had an AM1.5g efficiency of 5.5% and a 44-sun AM1.5d efficiency of 8.9%. The GaSb-on-GaAs cell was 1.0% efficient under AM1.5g and 4.5% at 44 suns. The lower performance of the heteroepitaxial cell was due to low minority carrier Shockley-Read-Hall lifetimes and bulk shunting caused by defects related to the mismatched growth. A physics-based device simulator was used to create an inverted triple-junction GaInP/GaAs/GaSb model. The model predicted that, with current GaSb-on-GaAs material quality, the not-current-matched, proof-of-concept cell would provide 0.5% absolute efficiency gain over a tandem GaInP/GaAs cell at 1 sun and 2.5% gain at 44 suns, indicating that the effectiveness of the GaSb junction was a function of concentration.

The physical limitations of lithographic imaging are ultimately imposed by the refractive indices of the materials involved. At oblique collection angles, the numerical aperture of an optical system is determined by nsin(θ) , where n is the lowest material refractive index (in the absence of any refractive power through curvature). For 193nm water immersion lithography, the fluid is the limiting material, with a refractive index of near 1.44, followed by the lens material (if planar) with a refractive index near 1.56, and the photoresist, with a refractive index near 1.75. A critical goal for immersion imaging improvement is to first increase the refractive indices of the weakest link, namely the fluid or the lens material. This paper will present an approach to immersion lithography that will allow for the exploration into the extreme limits of immersion lithography by eliminating the fluid altogether. By using a solid immersion lithography (SIL) approach, we have developed a method to contact the last element of an imaging system directly to the photoresist. Furthermore, by fabricating this last element as an aluminum oxide (sapphire) prism, we can increase its refractive index to a value near 1.92. The photoresist becomes the material with the lowest refractive index and imaging becomes possible down to 28nm for a resist index of 1.75 (and 25nm for a photoresist with a refractive index of 1.93). Imaging is based on two-beam Talbot interference of a phase grating mask, illuminated with highly polarized 193nm ArF radiation. Additionally, a roadmap is presented to show the possible extension of 193nm lithography to the year 2020.

Intermediate band solar cells promise improved efficiencies beyond the Shockley-Queisser limit by utilizing an intermediate band formed within the bandgap of a single junction solar cell. InP quantum dots (QDs) in an In0.49Ga0.51P host are a promising material system for this application, but two-step photon absorption has not yet been demonstrated. InP QDs were grown via metalorganic chemical vapor deposition, and a density, a diameter, and a height of 0.7 × 1010 cm−2, 56 ± 10 nm, and 18 ± 2.8 nm, respectively, were achieved. Time-resolved photoluminescence measurements show a long carrier lifetime of 240 ns, indicating a type-II band alignment of these InP quantum dots. Several n-i-p In0.49Ga0.51P solar cells were grown with both 3 and 5 layers of InP QDs in the i-region. While the solar cells showed an overall loss in short circuit current compared to reference cells due to emitter degradation, a sub-bandgap enhancement of 0.11 mA/cm2 was clearly observed, due to absorption and collection from the InP QDs. Finally, two-step photon absorption experiments have shown unambiguous photocurrent generation involving an intermediate band within the bandgap at temperatures up to 250 K.

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