Development of high-performance graphene-HgCdTe detector technology for mid-wave infrared applications

Abstract

A scalable, low cost, low power, and small footprint uncooled mid-wave infrared (MWIR) sensing technology capable of measuring thermal dynamics with high spatial resolution can be of great benefit to space and satellite applications such as remote sensing and earth observation. Conventional photodetectors designed to absorb MWIR band wavelengths have often been based on HgCdTe material and typically require cooling. However, through integration of bilayer graphene functioning as a high mobility channel with HgCdTe material in photodetectors, higher performance detection over the 2-5 μm MWIR band may be enabled and facilitated primarily by thus limiting recombination of photogenerated carriers in these detectors. This high performance MWIR band detector technology is being developed and tested for NASA Earth Science, defense, and commercial applications. Graphene bilayers on Si/SiO2 substrates are doped with boron using a spin-on dopant (SOD) process and then transferred onto HgCdTe substrates for enhanced mobility photodetection applications. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and secondary-ion mass spectroscopy (SIMS) were utilized for analysis of dopant levels and structural properties of the graphene throughout various stages of the development process to characterize the p-doped graphene following doping and transfer. The enhanced performance and functional capabilities of the room-temperature operating graphene-based HgCdTe MWIR detectors and arrays are thereby demonstrated through modeling, material development and characterization, and device optimization.