The nano-gratings are widely used in the optical measurement, integrated optics, optical information processing and other fields. It has been prepared by using electron beam lithography, etching, electroplating, nano imprinting, and LIGA technologies. In general, the fabrications of nano-grating require expensive and sophisticated equipment. The fabrication procedures involved are often complicated, therefore resulting in high cost and long production cycles. We report a new technology to fabricate nano-grating with much lower-cost. The technology is based on utilizing the high flexibility of PDMS and the nano-molding technology. Using this technology, nano-gratings can be fabricated in low-cost and no expensive or high precision equipment is needed. Because of the excellent replication property of PDMS molds, large number of gratings can be made with a single master mold.
GaSb based cells as receivers in thermophotovoltaic system have attracted great interest and been extensively studied in
the recent 15 years. Although nowadays the manufacturing technologies have made a great progress, there are still some
details need to make a further study. In this paper, undoped and doped GaSb layers were grown on n-GaSb (100)
substrates from both Ga-rich and Sb-rich solutions using liquid phase epitaxy (LPE) technique. The nominal segregation
coefficients <i>k</i> of intentional doped Zn were 1.4 and 8.8 determined from the two kinds of GaSb epitaxial layers.
Additionally, compared with growing from Ga-rich solutions, the growing processes from Sb-rich solutions were much
easier to control and the surface morphologies of epitaxial layers were smoother. Furthermore, in order to broaden the
absorbing edge, Ga<sub>1-x</sub>In<sub>x</sub>As<sub>y</sub>Sb<sub>1-y</sub> quaternary alloys were grown on both GaSb and InAs substrates from In-rich solutions,
under different temperature respectively.
Under high concentration the temperature of photovoltaic solar cells is very high. It is well known that the efficiency and
performance of photovoltaic solar cells decrease with the increase of temperature. So cooling is indispensable for a
concentrator photovoltaic solar cell at high concentration. Usually passive cooling is widely considered in a concentrator
system. However, the thermal conduction principle of concentrator solar cells under passive cooling is seldom reported.
In this paper, GaInP/GaAs/Ge triple junction solar cells were fabricated using metal organic chemical vapor deposition
technique. The thermal conductivity performance of monolithic concentrator GaInP/GaAs/Ge cascade solar cells under
400X concentration with a heat sink were studied by testing the surface and backside temperatures of solar cells. The
tested result shows that temperature difference between both sides of the solar cells is about 1K. A theoretical model of
the thermal conductivity and thermal resistance of the GaInP/GaAs/Ge triple junction solar cells was built, and the
calculation temperature difference between both sides of the solar cells is about 0.724K which is consistent with the
result of practical test. Combining the theoretical model and the practical testing with the upper surface temperature of
tested 310K, the temperature distribution of the solar cells was researched.