Fluorescent substance excited by low velocity electrons - is formed by shallow activator-doping of crystalline matrix

摘要

A novel fluorescent substance, excited by low velocity electrons, comprises a crystalline matrix and a luminescence-promoting activator which is doped in only a portion of the matrix extending to a depth of 0.5 microns from the matrix surface. Prodn. of the above substance involves (i) doping the activator into the crystalline matrix by ion implantation at an implantation energy of max. 100 keV; and (ii) annealing for max. 30 mins. USEU} In fluorescent display devices. ADVANTAGEU} The substance has increased luminance and is produced with increased yield and in a short time without deterioration of the surface of the crystalline matrix used to form the substance. PREFERRED PROCESSU} Ion implantation is carried out in an intermittent manner, the crystalline matrix being cooled during interruption of implantation. EMBODIMENTU} The fig. shows the relationship between relative luminance and implantation energy for a prior art substance and a Mn-doped ZnGa2O4 substance according to the invention. ZnGa2O4 powder (crystalline matrix) is doped with Mn at a dosage of 1 * 10 power 15 - 1 * 10 power 17/sq.cm. (corresponding to 0.03-3%) at an implantation energy of 10-100 (pref. 50) keV and an ion current of 1-100 (pref. 10) micro-A and is then annealed under the conditions: heating-up rate 100 deg C/sec., annealing temp. 600-1000 deg C, annealing time 10 secs. to 30 mins. and an annealing atmos. of a vacuum of 0.001 Pa. @GRAPHIC = O:EDNAIMAGES9431FR2698878.A1PG000001.DRG,562,426,0