Optical bistability based on the integration of a molecular nanomaterial in silicon photonics

Electro-optical bistability is a functionality which can be crucial for a wide range of applications as it can enable non-volatile and ultra-low power switching performance. We investigate the integration of a molecular-based nanomaterial presenting a Spin Crossover (SCO) effect in the silicon platform for enabling optical bistability. SCO is a spin-state switching phenomenon present in some molecular compounds such as the coordination complexes of transition-metal ions in which, under certain external stimulus (variation of temperature, pressure, electric field, or light irradiation), the electronic configuration can be switched between two molecular spin states, Low Spin (LS) and High Spin (HS) states. Furthermore, the spin state change is accompanied by a change in the structural, magnetic, and optical properties, as well as in the electrical conductivity and color. These properties vary as a function of the external stimulus following a hysteretic response, recognized as one of the most promising aspects of the system since hysteresis confers bistability and thus a memory effect. Finally, the SCO material can be synthetized as nanoparticles so that it can be easily integrated in the silicon platform and have the potential to allow optical switching at room temperature.