Uniform light emission from electrically driven plasmonic grating using multilayer tunneling barriers

Light emission by inelastic tunneling (LEIT) from a metal-insulator-metal tunnel junction is an ultrafast emission process. It is a promising platform for ultrafast transduction from electrical signal to optical signal on integrated circuits. However, existing procedures of fabricating LEIT devices usually involve both top-down and bottom-up techniques, which reduces its compatibility with the modern microfabrication streamline and limits its potential applications in industrial scale-up. Here in this work, we lift these restrictions by using a multilayer insulator grown by atomic layer deposition as the tunnel barrier. For the first time, we fabricate an LEIT device fully by microfabrication techniques and show a stable performance under ambient conditions. Uniform electroluminescence is observed over the entire active region, with the emission spectrum shaped by metallic grating plasmons. The introduction of a multilayer insulator into the LEIT can provide an additional degree of freedom for engineering the energy band landscape of the tunnel barrier. The presented scheme of preparing a stable ultrathin tunnel barrier may also find some applications in a wide range of integrated optoelectronic devices.