Near-infrared light emission and electronic properties of Au/Si ultrathin hyperbolic metamaterials*

Silicon-based optoelectronics is an emerging field of research for the development of low cost and energy efficient electronic devices for CMOS-compatible applications. One of these crucial challenges is the fabrication of a Si-based light emitting diode. Indeed, there have been extensive studies on developing an efficient Si-based light source, triggered by the potential of quantum-confined silicon for light emission. On the other hand, hyperbolic metamaterials (HMM) have been used to manipulate and enhance the spontaneous light emission, and thus are prominent candidate for light emitter devices. In this context, we investigate the efficiency of optical emission and transport properties in patterned ultrathin Au/Si HMM multilayers. We achieved an enhanced near-infrared light emission with an efficiency of the order of 0.85%, by taking advantage of the quantum-confinement of Si and the enhancement via surface plasmonic phenomena in the investigated Au/Si multilayers. These findings are in good agreement with our theoretical model based on first-principle calculations. We further show the transport measurements performed in the Au/Si multilayers, demonstrating quantum-size effects in the individual Au layers.