Vertical SiC taper with a small angle fabricated by slope transfer method

In this Letter, a slope transfer method to fabricate vertical waveguide couplers is proposed. This method utilises wet etched Si as a mask, and takes advantage of dry etching selectivity between Si and SiC, to successfully transfer the profile from the Si master into SiC. By adopting this method, a <2° slope is achieved. Such a taper can...

Efficiency enhancement calculations of state-of-the-art solar cells by luminescent layers with spectral shifting, quantum cutting, and quantum tripling function

Solar cells of which the efficiency is not limited by the Shockley-Queisser limit can be obtained by integrating a luminescent spectral conversion layer into the cell structure. We have calculated the maximum efficiency of state-of-the-art c-Si, pc-Si, a-Si, CdTe, GaAs, CIS, CIGS, CGS, GaSb, and Ge solar cells with and without an integrated...

Increased carrier generation rate in Si nanocrystals in SiO2 investigated by induced absorption

We report on investigations of optical generation of carriers in Si nanocrystals embedded in SiO2 matrix by time-resolved induced absorption technique. Results obtained for excitation below and above twice the bandgap energy h??<?2Eg and h??>?2Eg show very similar decay characteristics (within ?resolution ? 100 fs). When intensity of the signal...

Modulated photonic-crystal structures as broadband back reflectors in thin-film solar cells

A concept of a modulated one-dimensional photonic-crystal (PC) structure is introduced as a back reflector for thin-film solar cells. The structure comprises two PC parts, each consisting of layers of different thicknesses. Using layers of amorphous silicon and amorphous silicon nitride a reflectance close to 100% is achieved over a broad...