Analysis Of In_xGa_1-xSb Crystal Growth Mechanism In Space And Study On In_xGa_1-xSb Crystal Growth On Ground

In_xGa_1-xSb ternary alloy is a new type of semiconductor crystal material with the property that the lattice constant and the absorption wavelength can be adjusted.The lattice constant and the absorption wavelength can be adjusted in the range of6.096～6.479?and 1.7～6.8μm respectively.The wavelengths are in infrared region,that make the material can be used as the infrared photodetectors and the energy conversion,etc.Bacause of its property,In_xGa_1-xSb ternary alloy semiconductor can be used in many applications.But,due to the influenceof the buoyancy convection under the normal gravity、segregation and constitutional supercooling,it is difficult to grow In_xGa_1-xSb crystals in big size with uniform constitution and stably.To study the effects of gravity on In_xGa_1-xSb crystal growth,our group cooperating with JAXA used SJ-10 recoverable satellites to grow In_xGa_1-xSb crystal for 65 hours under microgravity.And the comparison experiment was made on ground.In this paper,we discussed results of the SJ-10 recoverable satellites experiment.And we refit the floating zone furnace to try to restrain the constitutional supercooling.Halogen light sources were replaced by the laser which was more advanced and stable as heat source to verify the influence of the laser floating zone method for In_xGa_1-xSb crystal growth.Main conclusions are as follows:1.Space environment is benefit to grow crystal.Under the microgravity,the influence of buoyancy convection was reduced to minimum.Compared to the In_xGa_1-xSb crystal grown on the ground,it can be found that,the crystal growth interface was stable and approximately complanate under the microgravity.At the start of the crystal growth,the grains grew rapidly toward neat and gradually grew up under the microgravity.The In_xGa_1-xSb crystal grew faster under the microgravity with less defects,better integrity,bigger crystal size,and more uniform distribution of elements;2.With laser heating,the shape of the melting zone can be better controled.And after simplifing the heating platform,more space can be used for all kinds of auxiliary equipment.Such as temperature measuring instrument can be added to monitor the crystal growth temperature;thermal imaging system can be added to monitor the temperature distribution in the melting area;And other in situ testing system can be added.3.The absence of contact with the walls of the container reduced the stress of the extrusion caused by volume expansion,resulting the defects were fewer in the crystals grown with the laser heating floating zone method.The temperature monitor showed that there was a befitting temperature gradient at the boundary of the melt zone during the crystal growth,while the temperature of the melting zone was stable and nearly homogeneous.Laue spot result and X-ray diffraction（XRD）result showed that it was possible to grow In_xGa_1-xSb（x=0.03）crystal with good quality under normal gravity.Due to the big separation between the solidus and liquidus,it was difficult to grow In_xGa_1-xSb crystal with high In content at present.The key in the future will be to explore a stable growth process,reduce the instability of the melting zone during crystal growth,and control the temperature at the crystal growth interface precisely to guarantee the uniformity of crystal.