A UV‐light‐emitting homojunction ZnO LED is grown by radiofrequency sputtering at high temperature, improving the structural, electrical, and optical properties of the n‐ and p‐type ZnO layers. The figure shows a comparison of the electroluminescence spectra of A) a p–n homojunction ZnO LED and B) a ZnO LED with Mg0.1Zn0.9O layers used as energy barrier layers. Such materials are of interest for their potential use in long‐lifetime solid‐state lighting, high‐density information storage, secure communication, and chemical/biological‐agent monitoring.