Tunable Broadband Photodetectors Based on 2D Heterostructures

Photodetection over a broad spectral range, especially in both infrared (IR) and deep ultra-violet spectral regions, is crucial for optoelectronic applications such as sensing, imaging and communication. From night-vision goggles to heat-seeking missiles, the military is constantly looking for advantages from novel IR photodetectors, which could give deployed soldiers the enhanced situational awareness they need to win in contested environments. The goal of this proposal is to achieve room-temperature tunable broadband photodetection via the construction of two-dimensional (2D) heterojunctions, with an emphasis on their IR photodetection over a 1–4 μm range.

The extraordinary electronic, optical and mechanical properties of 2D materials and their heterostructures make them promising candidates for optoelectronics, specifically for tunable IR photodetection owing to their layer-dependent optoelectronic properties. The synergistic effect of 2D/2D heterostructures provides a unique approach to lower the noise (e.g., dark current) while increasing the detector responsivity and extending the response range for the short- and mid-wave IR photodetection applications. Three main scientific challenges this project addresses include (1) balancing the trade-off between light absorption and dark current of 2D materials, (2) producing 2D material in a suitable size and quantity with desirable electronic properties, and (3) fabricating field-deployable flexible functional devices that could operate at ambient conditions.

It is anticipated that this study will lead to the development of a new generation of on-field detector technology that gives soldiers new and improved capabilities for sensing personnel and motion under poor visibility conditions. Moreover, the proposed project activities will also advance institutional research and educational capabilities in the Department of Chemistry and Biochemistry at North Carolina Central University, a historically black university and a primarily undergraduate institution, and strengthen the pipeline for the advancement of underrepresented minorities in science, technology, engineering and math (STEM) disciplines.