Photodetector detecting specific range of visible light in vertically-stacked graphene/hBN/metal

Many people have researched photodetectors made with 2D materials due to its attractive properties such as flexibility and high mobility. the 2D semiconductor is very useful to detect a full range of visible light because of its band gap which is estimated to be 1.9 eV. But it is very difficult to detect specific range of visible light. Because this photodetector converts light photons into current depending on its band gap, and the band gap can be changed only by a type and thickness of 2D material.
In this poster, we introduce a photodetector which can change the detectable range of visible light independently of the band gap. When the graphene absorbs energy of photons which is larger than the barrier height, electrons excited by photons can be transmitted from fermi energy level of graphene into conduction band of hBN. And as the graphene’s fermi energy level can be controlled by external electric field, we can modulate the transmitted electrons into conduction band of hBN by controlling the barrier height. in this experiment, we measured a photocurrent at 640 nm, 532 nm, 405 nm. and we confirmed that the detectable range of the light shift according to the drain voltage. And we also calculated energy of incident light by an algorithm which is related to deconvolution