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A high efficiency CdS/CdTe solar cell was designed with a reduced CdTe absorber-layer thickness and a distributed Bragg reflector (DBR) as an optical reflector and a ZnTe layer as back surface field (BSF) layer. Simulation results showed that with combination of DBR and BSF layers and 0.3 µm thick CdTe, the conversion efficiency was increased about 3.2% as compared with a reference cell (with 4 µm thick CdTe layer). It was also shown that the efficiency can be increased up to 6.02% by using a long carrier lifetime in the absorber layer. Under global AM 1.5G conditions, the proposed cell structure had an open-circuit voltage of 1.062 V, a short-circuit current density of 24.64 mA/cm², and a fill factor of 81.3%, corresponding to a total area conversion efficiency of 21.02%.

We show that a periodic nanostructure patterned into a polymeric or indium tin oxide ͑ITO͒ surface is capable of aligning liquid crystal ͑LC͒ molecules. Gratings of different depths were created on thin polymeric or ITO surfaces with submicron and micron periods by superposition of ultraviolet plane waves. The depth of the gratings was varied by changing the fluence of the laser. This method allows to pattern orientations over small areas and does not suffer from the disadvantages of rubbing based alignment methods. LC alignment was tested by forming twisted nematic cells. Anchoring energies were calculated from measurements of the twist angles.