Horizontal travelling heater method growth of Hg1−xCdxTe with crucible rotation

A horizontal travelling heater method (THM) for growing cylindrical cyrstals from a partially filled solution zone has been investigated for the first time. By applying ampoule rotation, the whole cross section of the crystal is successively brought into contact with the liquid solution, which is effectively stirred by forced convection. This approach was used to grow single-crystalline Hg1−xCdxTe ingots from a Te-rich solution zone. The structural perfection and metallurgical homogeneity are equivalent to vertically-grown THM material

Comparison of two approaches to forced convection in crystal growth of II-VI compounds by THM

Hg1 - xCdxTe and Cd1 - xZnxTe single crystals were grown by the tracwelling heater method (THM), applying two different techniques of artificially stirring the solution zone. Accelerated crucible rotation (ACRT) was used in a vertical growth arrangement and compared a technique with constant rotation around the horizontal axis of the ampoule. The dominant hydrodynamic mechanisms of noth methods are discribed by the rotating disc model and are suggested to be almost identical with respect to the growth conditions at the interface. Convective flow is effectively enhanced adhacent to the growing crystal, where the matter transport is regarded as the rate-limiting step of solution growth. Inclusion density analysis by IR microscopy was used to characterise the crystals of Cd1 - xZnxTe grown at different rates. It was shown that forced convection allows an increase in the crystal growth rate from a few mm day-1 with ACRT or horizontally rotating THM

Growth of Hg1−xCdxTe single crystals by travelling heater method under accelerated crucible rotation conditions

The accelerated crucible rotation technique (ACRT) has been applied to the THM growth of Hg1−xCdxTe crystals to grow the crystals at a higher rate. These higher growth rates, which should be achieved by extending the regions of conventional stirring towards the interfaces, have been used in an attempt to explain the results in terms of simple constitutional supercooling arguments. Some different ACRT cycles which fulfil simple hydrodynamic and geometric criteria have been studied. The grown crystals were investigated with respect to their metallurgical homogeneity and their structural perfection. These properties have not been degraded by increasing the growth rate from 1.5 to 8.5 mm per day