Both normal and ripple-like CdS microbelts (MBs) were prepared and their optical properties were investigated by photoluminescent and Raman measurements. One emission at ∼510 nm for normal CdS MBs and two emissions around 513 and 725 nm for ripple-like one were observed. The longitudinal optical phonon mode (1LO) at ∼304 cm−1 and its overtone mode (2LO) at ∼605 cm−1, multiphonon processes and surface phonon peaked at 281 cm−1 were observed, the larger integrated intensities ratio of 2LO to 1LO indicates a strong exciton-phonon coupling interaction. Furthermore, more than 4 times larger enhanced Raman scattering for the ripple-like MBs than the normal one were observed, and the enhanced Raman scattering is mainly associated with the surface defects, which lead to a strong Fröhlich interaction through the charge transfer, not by the deformation potential through surface plasmon enhancement.

GaN/InGaN lighting-emitting diodes with different mesa structures are studied. The current-voltage characteristics, light output power, luminous efficiency, and peak wavelength of the GaN/InGaN lighting-emitting diodes with different mesa patterns are compared. It shows that the current-voltage characteristics of the chips with more mesa areas are im- proved greatly by reducing the current crowding. With higher injection current the light output powers of GaN-based LED with more mesa areas are enhanced. And the chips with more P-electrode area have a smaller red shift and a little bit blue shift due to the reduction of the current crowding

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To overcome the difficulties in the fabrication of the nanoimprint mold with lin ewidth smaller than 50nm, we deposited a-Si/SiNx multilayer films in plasma enhanced chemical vapor deposition system and then prepared the relieo-n anomold on the cleaved section of the multilayer films by selectively etching or reactive ion etching process. Due to the slow deposition rate, the thickness of the sublayer, and therefore the size of the strips and grooves can be controlle d on the nanometer scale by altering deposition time. The smallest width we get by now is the 20nm strips and 20nm pitches，which is better than that fabricated by electron beam lithography.

Quantum dots sensitized solar cells (QDSCs) play a key role in the new generation photovoltaic devices due to their low cost and easy fabrication process. The absorption spectrum of quantum dots can be tailored by controlling grain size, and multi-exaction generation. QDSCs using inorganic compound QDs replaces the dye as a sensitizer, which is able to solve the stability of the dye sensitized solar cells. However, further improvement of the conversion efficiency of QDSCs is still a major issue for their application. Recently, tailoring electronic properties of the counter electrode(CE) in QDSCs using different materials has been considered as a promising way to improve photovoltaic performance of QDSCs. This article reviewed the quite recent progress of CE in QDSCs based on synthesis method, surface microtopography and crystal structure. This review gave a panorama of metal chalcogenides, composite materials, hybrid materials, muti-component metal chalcogenides, conductive polymers, and carbon CE materials for QDSCs, while the influence of CE materials on the charge transfer impedance, the electron transport process, catalytic properties, and I-V characteristics was stressed in detail. Finally, an outlook on the future challenges and pros