Study On Growth Of Sapphire (Al₂O₃) Crystal By Efg

Sapphire is Al₂O₃ crystal including some Ti⁴⁺ and Fe³⁺.It is a simple oxide crystal of hexagonal crystal system. It has very stable chemical and mechanical properties .It also has good thermal conductivity and electric insulation.Sapphire is widely used as various optical elements,infrared military equipments,satallite space technology,high intensity laser window material and so on. Sapphire is also the most ideal substated material for LED and LD.Designing rational process parameters,a high quality sapphire was grown by EFG method(Edge-defined , Film-Fed Growth).The dislocation and UV-VIS absorption spectra were also studied.(1) The crystal growth procedure was optimized. The relationship between the material handling,temperature field,pulling velocity,heat insulating materials growth diretion,die and the sapphire quality was also investigated.(2) The main defects containing crackings bubbles and wappage of sapphire were analyzed, and the measurement of decreasing or eliminating defects were put forwarded.(3) The UV-VIS absorption spectra was measured and the colouration mechanism of sapphire was discussed.