Growth And Characterization Of Selenium (Se) Doped Gallium Antimony (GaSb) Bulk Single Crystals Using VDS Technique

In vertical directional solidification (VDS) technique bulk single crystal is grown without the seed and without any contact between the ingot and the ampoule wall. The growth of Se doped GaSb bulk crystal was carried out using VDS technique. This growth chamber has been designed and fabricated by considering rotation ratio, translation ratio along with special axial and radial temperature gradient with optimized growth parameters. High purity Gallium and Antimony was taken as the source material and Selenium as doping material. This mixture was then loaded in a quartz ampoule which has conical angle >20 degrees. The ampoule was than filled with high purity argon gas and sealed at low pressure (200 torr). The temperature was raised up to 850 degrees c. The ampoule was then positioned inside the hot furnace vertically and lowered at 4mm/hr growth rate. Then it was kept for cooling and annealing at 400 degrees c for 12hrs. From the grown ingot substrates were obtained in wafer form by cutting the crystal using diamond cutter. Then it is polished to get a mirror finish. The characterization of sample is studied by EDAX, microstructure, hall measurement and optical property by FTIR. The GaSbSe samples show high resistivity and mobility.