(Invited) Photodetection from Mid-IR to UV Using Semiconductor Heterostructures

Abstract

I will discuss the use of semiconductor heterostructures with proper bandgaps and architectures to detect photons with different wavelengths. First, for the most pursued visible light detection, hybrid perovskites have aroused lots of interest because of their exceptional properties, such as low-cost solution processing, tunable direct bandgap, high light absorption and long carrier diffusion length. Our experiments demonstrate that combining 3D perovskites with high-mobility 1D carbon nanotubes or 2D two-dimensional metal dichalcogenides significantly enhances charge transport and device performance. Second, we demonstrate a mid-infrared hybrid graphene photodetector enabled via coupling graphene with a narrow bandgap semiconductor Ti2O3. This hybrid photodetector achieves high responsivity of ~200 A/W in a broadband wavelength range up to 10 μm. Finally, using epitaxial ferroelectric/semiconductor junctions with a current-perpendicular-to-plane geometry, we achieve a colossal X-ray-induced photoconductivity with a magnitude of six orders. This X-ray-induced persistent photoconductivity persists for days with negligible decay. This new device scheme open a new route towards X-ray sensing and imaging applications.