Electroluminescence by impact excitation in ZnS:Mn and ZnSe:Mn Schottky diodes

Measurements have been made of the variation of the quantum efficiency of electroluminescence as a function of applied field in ZnS:Mn and ZnSe:Mn Schottky diodes. Under very high fields, the quantum efficiency unexpectedly reaches a maximum and then drops. An explanation is proposed which depends on the details of the band structures of ZnS and ZnSe.