2D Materials Market to Expand With Newly Developed Photodetector Created By Two-Dimensional Layered Materials
Posted On July 14, 2021
High dark current can cause damage to the performance of infrared photodetectors (a device with the ability to detect photons in the form of infrared radiation). For numerous years, all solutions for blocking dark current discovered have used the electric field within the detectors. In 1935, Bell Labs had managed to produce the Si-based PN junction; since then, the built-in electric field in the depletion region has been used as the primary technical route to block dark current. However, the problem lies with the PN junctional infrared photodetectors, the high SRH (Shockley-Read-Hall) recombination, and surface recombination in the depletion region as they seriously limit the suppression of dark current.
To overcome this hurdle, researchers have successfully devised an alternative solution that can potentially suppress dark current in photodetectors. The new approach is based on the use of vdW (van der Waals) heterostructures. The move can be considered to bring a huge impact on 2D Materials Market as the research presents visible and mid-wavelength infrared unipolar barrier photodetectors made up from 2D materials and comprised of band-engineered vdWheterostructures. The novel aspect of the research is that engineers, for the first time, have introduced a new device structure beyond the PN junction – “the unipolar barrier structure."
The research team revealed that the main aim behind the published work was that vdW unipolar barrier heterostructures could help suppress dark current within the photodetectors. This can be achieved by blocking majority carriers; furthermore, these structures could be used to eventually enable infrared photodetectors to operate at high temperatures, resulting in remarkable performances. The presented vdW unipolar barrier heterostructures could be an easy solution to the bottleneck of dark current and can also enhance the performance of infrared photodetectors. Further, they can, in time, come to enable the 'lab-to-fab' transition of 2D (Two-Dimensional) materials in infrared applications.
In the situation of nbn, the conduction band barrier can efficiently bar the movements of the electrons from the contact layer to absorption layer, making the surface current attenuated. Simultaneously, the SRH current is reduced as the distribution of the depletion region is near the wide-bandgap barrier layer. In addition, the Auger recombination responsible for determining the hot noise can also be suppressed with the reduction in carrier concentration in the absorption layer.
The research also demonstrates that unipolar barriers can help suppress the dark current by presenting a large bandgap barrier layer. Hence, unipolar barrier photodetectors can operate at a higher temperature, in contrast to a PN junction with the same dark current, or they can have higher performance at the same temperature. In the future, these photodetectors created by their team could help improve sensing and imaging devices. Furthermore, the work could inspire another group to build similar types of photodetectors using 2D layers of material.