Optimization of the growth interface during the growth of ZnTe crystal by the temperature gradient solution growth technique

In order to optimize the growth interface during the growth of ZnTe crystal by the temperature gradient solution growth (TGSG) technique, a cylindrical ampoule pedestal is designed, which consists of a mullite sheath and a graphite core. A finite element model is established to simulate the effects of the pedestal on the transport phenomena and the growth interface during the growth. The results show that when the growth begins, there are two clockwise vortexes in the solution. The lower one is close to the growth interface and the upper one occupies the rest of the solution. The lower vortex vanishes very soon, and the upper one keeps shrinking and moving upwards. After the lower vortex disappears, the solute (ZnTe) transfers to the growth interface only by diffusion. The growth interface, which is convex first becomes flat when the first third of the ingot has grown, and turns to concave after that. The depth of the growth interface is far less than that in the growth without the pedestal. Distortion of the growth interface in the growth without the pedestal does not occur in the current growth. The optimized growth interface should be helpful to improve the grain size and the crystalline quality.