Single crystal growth of compositionally graded InXGa1−XAs

Directional solidifications were carried out by vertical Bridgman method with GaAs seed and In0.3Ga0.7As feed. Experimental results show that seeding was more successful in the case of low temperature gradient than a steep one. Lattice mismatch of the seed and the grown crystal is small. Single crystals were reproducibly obtained at low temperature gradient and at small lattice mismatch in these experiments. The grown single crystal is longer than 20 mm with a diameter of 14.5 mm. Indium concentration along the growth axis increased as crystal growth proceeded, which agrees with a compositional profile modeled from the InAs–GaAs pseudo-binary phase diagram. Electron mobility of initial grown crystals obtained at lower temperature gradient is higher than that of crystals grown at higher temperature gradient.