Electroluminescence in Potassium Iodide Single Crystals Containing Potassium Colloids(Ⅰ)

In order to investigate the phenomenon of electroluminescence,EL,in KI single crystals containing potassium colloids under alternating high electric field it is essential to establish a high reliable method for introducing potassium colloids in KI single crystals.Both methods of additive coloration and of electrolytic coloration were compared each other in various experimental points of views.The additive coloration was carried out by employing a modified Van Doorn's method.The electrolytic coloration was performed by using a newly designed vertical setup furnace.Through the optical spectroscopic measurements of thus obtained colored KI specimens the F-center and its aggregate centers,e.g.,F_2-center,as well as potassium colloids were identified.Various observations of EL in terms of the dependence of applied voltages and temperatures were performed by using KI specimens containing potassium colloids and F- as F_2-centers.Especially,the contribution of the F-center to the ELdevelopment was examined in detail.The pH measurement of densely colored KI specimens was also carried out to obtain the information about the distribution of the potassium colloids in crystals.It was found that pH analysis is one of the simple method for evaluating the concentration of potassium colloids in KI crystals.Furthermore,brief discussion is given concerning the characteristic development of EL in colored KI crystals.カリウム・コロイドを含むKI単結晶における電界発光現象についての機構を明らかにするための第一段階として，カリウム・コロイドのKI単結晶への導入法を確立するために付加着色法と電解着色法との比較が行われた。その結果，電解着色法がいくつかの点で付加着色法より優れていることが判明した。得られた試料を用いて電界発光強度の印加電圧依存性と温度依存性についての調査が行われた。電解発光におよぼすF中心の影響に注目して解析を行い，F中心の存在により発光の出現が抑制されることがわかった。さらに着色試料を用いてpH測定を行うことにより，着色KI結晶中におけコロイドの濃度の評価法について検討した