Preparation Of Nano-templates And Nano-texture On Crystalline Silicon

Solar power is attracting extensive attention due to it is a clean, endless green energy. In recent years, photovoltaics industry developed rapidly. Especially in our country, the scale of China’s PV industry has been ranked first in the world. However, the study for photovoltaics is still weak. It is necessary and important to enhance the study level on photovoltaics field.Due to the high efficency, high stablity and low cost, the crystalline silicon solar cells dominate the world PV market. To increase the application of the solar cells, the improvement of the efficency and the decreasment of the cost are important. One of the useful ways to improve the efficency of the solar cells is the reducement of the light reflection on the silicon surface. This study focus on the preparation of the light-trapping structures,which includes nanotemplates preparation and nanotextured surface preparation.The conclusions are the followings:1. The home-made experimental apparatus for the preparation ofnanotemplates were designed and builded. The experimental apparatus are consists of two parts. The upper part is used to pull the films, and the bottom part is used to collect. Single layer nanotemplates on mechanical polished silicon surfaces were obtined by using Polystyrene (PS) nanospheres suspension at different temperatures and reaction times. On the same conditions, single-double layer mixed PS nanospheres templates were prepared on chemical polished wafer surfaces.2. The nanotemplates were obtained by spin coating of PolymethylMethacrylate/Polystyrene (PMMA/PS) blend solution and then selectively removing the PS phase. The scanning electron microscopy (SEM) was used to investigate the morphology and structure of the samples. It is founded that the holes randomly dispersed in the PMMA films, which opens basic round aperture in the 200 nm-300 nm. Concentrations, annealing temperature and organic solvents affected the micro-structure of the nanoporous film, via the influence on the solvent evaporation rate and the phase separation process for two. At last, the optimized parameter were applied to obtain the good nanotemplates.3. This paper presents a new method for nanotexturing - NH4F solution system with ultrasonic and ultraviolet irradiation. The tiny nano-protrusion structures were prepared on the surface of the pyramids which came from normal alkali etching method. By changing the concentrations of NH4F solution, light intensity voltage, the reaction times, the obtained nanotextureing structure can reduce the light reflection on short wavelength region. This method is stable, non-toxic and non-metal ions involved.