Effect of temperature gradient on microstructure and properties of GaSb crystals grown with Bridgman method

Abstract

GaSb crystal ingots were grown with vertical Bridgman method. The effects of temperature gradient on the structure and properties of GaSb crystals were investigated. When the temperature gradient increased from 5 to 7 °C cm-1, the crystallinity of the ingot improved, the dislocation density decreased by 55%, from 3928 to 1785 cm-2; the carrier mobility increased by 29.6%, from 868 to 1125 cm2 V-1 • s-1; the resistivity decreased 50.6%, from 12.45 to 6.332 10-3 Ω • cm; the infrared transmission increased from 27% to 32%. When the temperature gradient increased from to 7 to 9 °C cm-1, the crystallinity of the ingot deteriorated obviously, the dislocation density increased 4.38 times, from 3928 to 9609 cm-2; the carrier mobility decreased by 52.4%, from 1125 to 738 cm2 V-1 • s-1; the resistivity increased 6.2 times, from 6.332 to 23.94 10-3 Ω • cm; the infrared transmission decreased from 32% to 25%.