Investigation of the light emission in the local tunnel junction and its dependence on the contact surface morphology

In this paper we investigate light emission in a tunnel junction between a thin gold film on a glass substrate and a gold-coated tungsten tip of a scanning-tunneling microscope probe. The experiments show that the size of grains in the gold film surface dramatically affects the intensity of emissions. We demonstrate that a decrease in the grain aspect ratio provides an increase in the quantum yield of the tunnel-junction emission.