Evolution from random lasing to erbium-related electroluminescence from metal-insulator-semiconductor structured light-emitting device with erbium-doped ZnO film on silicon.

A type of metal–insulator–semiconductor (MIS) structured light-emitting device (LED), where a semitransparent gold (Au) film, a polymethyl methacrylate film, and an erbium (Er)-doped ZnO (ZnO:Er) film on a silicon substrate act as the "M", "I", and "S" components, respectively, has been prepared. With increasing forward bias with the positive voltage connected to the semitransparent "M" (Au) electrode, such LED first exhibits random lasing (RL) from the ZnO host itself and is then electroluminescent with the characteristic emissions from the Er³⁺ ions incorporated into the ZnO host. Based on the energy band diagram and the analysis of carrier transportation for the ZnO:Er-based LED applied with different forward bias voltages, the evolution from the RL to the Er-related electroluminescence as mentioned above has been tentatively explained. [ABSTRACT FROM AUTHOR]