Gate Tunable and Multifunctional Metal Nitride Zero Index and Plasmonic Heterostructures for Advanced Optical Sensing and Energy Harvesting

The optical response of epsilon-near-zero (ENZ) materials has been a topic of significant interest in the last few years as the electromagnetic field inside media with near-zero permittivity has been shown to exhibit unique optical properties, including strong electromagnetic wave confinement, non-reciprocal magneto-optical effects, and abnormal nonlinearity. These ultrathin ENZ materials are promising for the enhancement of quantum emission for optical sensing and enhanced absorption/emittivity for energy harvesting. WhileENZ optics have been extensively investigated in the last few years, the previous studies suffer from several limitations, including (i) lack of precise control of carrier distribution for efficient ENZ mode excitation, (ii) lack of efficient tunability due to the fixed conductivity of the noble metal/semiconductor, (iii) high optical loss due to the amorphous or high surface roughness of the film, and (iv) narrow bandwidth of operating wavelength (<10 nm). Until we can solve these problems and manipulate and enhance the zero-index optical dynamic, we cannot develop efficient nanoscale ENZ optical applications for quantum optical sensing and energy harvesting. The objective in this collaborative research project is to establish an efficient material and electrical management of the enhanced optical properties, such as quantum emission, optical phase and absorptivity/emissivity, of metal nitride zero-index and plasmonic heterostructures for nano-optoelectronic devices.