Undoped ZnSe single crystal growth by the vertical Bridgman method

Abstract We have successfully grown twin free undoped ZnSe crystals by the vertical Bridgman method. The single crystals were as large as 25 mm in diameter by 25 mm in length. The macro-defects, such as voids and twins, were reduced drastically by selecting the downward velocity of the crucible and the angle of the crucible cone. Large twin free crystals were obtained when the velocity was not more than 4 mm/h and the crucible cone angle was either 30° or 45°. For crucible velocities greater than 4 mm/h, only polycrystalline material was obtained. In high purity ingots, the concentrations of various impurities were found to be either less than 1 ppm or under the detection limit.