Research Projects

Photodetectors are crucial optoelectronic devices used to detect different regions of the electromagnetic spectrum based on their sensitivity. The sensitivity depends on the energy band gap of the material used. NIR to MIR photodetection is desirable but faces challenges in room temperature operation. 2D materials like graphene, transition metal chalcogenides, and black phosphorous (bP) have favorable properties for photodetection applications, including layer-dependent optical band gap and van der Waals stacking between layers. These properties allow for tuning the sensitivity of the photodetector in different regions of the spectrum and enabling the fabrication of van der Waals heterostructure-based devices. Van der Waals materials also have large optical anisotropy, allowing for polarization detection. However, heterostructure-based photodetection devices suffer from dark current, which limits detectivity at weak signals. To resolve this issue, a hexagonal Boron Nitride (hBN) layer can be stacked at the heterostructures, causing asymmetric tunnelling between photogenerated signals and dark signals. The proposed photodetection device will consist of three terminal devices with two van der Waals heterostructures, controlling the device in a batter way to reduce dark current effects.