Hot-electron picture of light emission from tunnel junctions

Metal-insulator-metal tunnel junctions emit optical radiation when biased at voltages in the range 2-4 V. We argue that a complete picture of this radiation process includes hot electrons, which excite surface electromagnetic resonances, which are in turn coupled to external radiation through surface roughness. This picture is supported by measurements of the temperature and second-metal-electrode thickness dependence of the emission intensities, and by light emission from surface plasmons excited by optical pumping and by charge injection. © 1983 The American Physical Society.