Researchers develop a high performance polarization sensitive photodetector that can be used in a variety of civil and military applications.
Polarization-sensitive photodetectors (PSPDs) are useful in various military and civil applications like bio-imaging, remote sensing, night vision, and helmet-mounted sights for fighter pilots. PSPDs use materials having a refractive index that changes with polarization and direction of propagation of light. These materials can detect photons of a desired linear polarization. The advantage of this device is that for traditional photodetectors to realize polarized light detection, they need to combine optical filters with polarizers, which increases the size and complexity of devices. On the other hand, PSPDs with advanced materials as mentioned above can result in a small-size photodetector.
Researchers from China and South Korea have developed high-performance PSPDs on 2D semiconductors. One dimensional nanomaterials such as nanowires, nanoribbons and nanotubes, have been used as the sensitive materials for PSPDs, which can detect the changes in polarization of light without any optical filters or polarizers.
The materials that can detect polarization of light are called optically anisotropic materials. 2D semiconductors like SnS, ReS2, GeS2, GeAs2, AsP and black phosphorus (BP) exhibit an in-plane anisotropy behavior in carrier transport, thermal conductivity, electrical conductivity, thermoelectric transport and optical absorption processes. Among these materials, BP based PSPDs have the highest photocurrent anisotropy ratio of 0.59 (default value is 1 which means material is fully isotropic).
But BP-based photodetectors are prone to degradation. Therefore, the researchers suggest using 2D layered indium selenide (InSe), which also has high carrier mobility and is more stable than BP in an atmospheric environment. The researchers prepared a stable layered β-InSe and achieved high performance filter-free PSPDs with high photocurrent anisotropic ratio of 0.70.
Further information regarding the research can be found at http://dx.doi.org/10.1093/nsr/nwab098.