Large emission current density of LaxCe1-xB6 high quality single crystals grown by floating zone technique

The high quality LaxCe1 B-x(6) (x = 0, 0.2, 0.4, 0.6, 1) single crystals with large emission current density have been successfully grown by floating zone method. The crystal structure, crystal quality and emission properties of LaxCe1 B-x(6) single crystals were characterized by 360 degrees Phi scanning single crystal diffractometer, X-ray Laue diffraction and the thermal electron emission measurements. It is found that the as-grown crystals have a good crystal quality without subgrains and twin crystal phenomenon. The thermionic emission measurement results show that the maximum emission current density on (100) surface of La0.2Ce0.8B6 single crystal is 71.2 A/cm(2) at 1873 K under an applied voltage of 800 V, which is larger than the reported values in the literatures up to now. Furthermore, the crystals with different components also show a higher emission current density such as 53.8A/cm(2) for La0.4Ce0.6B6 and 53.3 A/cm(2) for CeB6 single crystals. The field emission single tip made by LaB6 single crystal shows a superior performance than the polycrystalline LaB6 field emission tip and its field enhancement factor (beta) is 36,231 cm (1). Thus, the LaxCe1 B-x(6) single crystals will have promising application prospects as a hot or cold cathode. (C) 2012 Elsevier B.V. All rights reserved.