Numerical simulation of infrared photodetectors with Au grating by FDFD method

Quantum-well infrared photodetectors have been studied extensively due to their night vision, astronomy and environmental monitoring research in recent years. However, responsivity and detectivity are relatively low in these photodetectors without the Au gratings. Therefore, the Au grating will be employed on the surface of photodetector with periodic structure due to the principle of spoof plasmon resonance. The new design mainly aims to enhance the absorption in the QW active region based on the Au grating and can be numerically simulated by using finite-difference frequency-domain method. With optimal grating parameters, the absorption can be enhanced by 250 times compared with that in the reference structure without grating. The theoretical results provide the realistic organic infrared photodetectors with theoretical basis and technical support.