Optimization and Experimental Demonstration of Plasmonic Enhanced Internal Photoemission Silicon Schottky Detectors in the Mid-IR

Plasmonic enhanced Schottky photodetectors operating on the basis of the internal photoemission process are becoming an alternative for the more conventional photodetectors based on interband transitions for light detection in the infrared. This is because such detectors typically consist of silicon and CMOS compatible metals, thus, allowing low cost and large scale fabrication. Most of the reports so far were focused on measuring the responsivity of the device. Here, we provide a detailed analysis for the optimization of internal photoemission based devices in terms of figure of merits such as signal-to-noise ratio (SNR) and noise equivalent power (NEP). Following the analysis, we experimentally demonstrate the operation of pyramidally shaped, silicon-based, internal photoemission detectors in the mid-infrared. The measured devices are capable of photodetection at wavelengths up to similar to 2.5 mu m. This paves the way for the use of plasmonic enhanced silicon photodetectors for a broad range of applications including mid-IR circuitry and biochemical sensing.