Improving efficiency of quantum dot infrared photodetector by using photonic crystal framework in the active layer

For flat quantum dots (QDs), such as MBE-grown QDs, the electric field component in the incident direction of the light (E_z) is critically important for efficient light-matter interactions inside QDs. The metal photonic crystal (MPC) which is made of a thin metal film perforated by two-dimensional (2D) hole arrays can be integrated on the top of the absorption region in quantum dot infrared photodetectors (QDIPs) to increase the photocurrent. Light transmitting through the MPC can create an E_z-directed field as the role of surface plasma waves (SPWs). In large-scale QD infrared radiation focal plane array, the light is needed to be injected from below the bottom of the substrate as the metal contact layer on the surface of the QDIP can reflect a lot of light. So how to reduce the light reflection from substrate and enhance the E_z at the same time is very important in this situation.