A new low-voltage Si-compatible electroluminescent device

Thin film direct-current electroluminescent devices with ZnS:Mn as the active light-emitting layer have been fabricated on Si wafers. The devices incorporate a high-efficiency electron injector layer capable of passing high current densities (>10 -2 A cm -2 dc) through the active layer. A useful luminance of 78 fL has been achieved at 48V, significantly lower voltage than for conventional ac thin film or dc powder electroluminescent devices. The structure also includes a potential energy step at the interface between SiO 2 and ZnS due to the difference in electron affinities which offers the possibility of hot electron injection into the active layer. The unique combination of efficient cathode emission and hot injection possible in these devices suggests that a solid state analogue of the cathode ray tube may be realizable.