Improvement of electron diffusion lengths in polycrystalline silicon wafers by aluminium
In order to improve the electron diffusion lei wafers, an aluminium layer was deposited on the back sul 2 h. It was found that Ln is increased, provided the initi; density of dislocations is larger than 5 x 104 cm-2. Backsig to explain the results and it is assumed that dissolved c
High efficiency multicrystalline silicon solar cells
A detailed investigation of quality enhancement techniques, such as PECVD SiO2/SiN deposition and forming gas anneal (FGA) for defect passivation, and A1 treatment for defect and impurity gettering, was conducted on several promising multicrystalline Si materials. The PECVD SiO2/SiN coating increased the bulk lifetime by a factor of 1.3 to 1.7, and decreased the surface recombination by a factor of 5–22, depending upon the multicrystalline material. FGA in conjunction with A1 treatment improved the EFG sheet Si cells efficiency by 5.3% absolute, with 2.6% improvement resulting from the FGA alone, 1.5% from A1 gettering alone, and 1.2% from A1 diffusion and FGA interaction. Cells fabricated on various multicrystalline materials were in the efficiency range of 14.0–17.7% with highest efficiency on cast silicon from Osaka Titanium Corporation.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.