A study published in Nature Nanotechnology (2013) demonstrates highly efficient gate-tunable photocurrent generation in vertical heterostructures of layered materials, specifically graphene-MoS₂-graphene and graphene-MoS₂-metal junctions. The research shows that these structures can generate photocurrents with high external quantum efficiency (up to 55%) and internal quantum efficiency (up to 85%) by modulating the band slope and photocurrent generation through an external electric field. The vertical heterostructures allow for broad-area photocurrent generation, which is more efficient than lateral devices. The study also highlights the ability to control photocarrier generation, separation, and transport processes using an external electric field. The results show that the photocurrent can be modulated by adjusting the gate voltage, with the polarity and amplitude of the photocurrent being significantly influenced by the external field. The study further explores dual-gated devices, where both top and bottom gates can be used to modulate the photocurrent. The research demonstrates that the unique properties of vertical heterostructures, including the optical transparency of graphene and the partial electrostatic transparency of the material, enable efficient modulation of photocurrent generation. The study also compares the performance of vertical heterostructures with conventional photodiodes, showing that the vertical structures offer superior performance in terms of photocurrent efficiency and tunability. The findings have implications for the development of future photodetection and photovoltaic devices.A study published in Nature Nanotechnology (2013) demonstrates highly efficient gate-tunable photocurrent generation in vertical heterostructures of layered materials, specifically graphene-MoS₂-graphene and graphene-MoS₂-metal junctions. The research shows that these structures can generate photocurrents with high external quantum efficiency (up to 55%) and internal quantum efficiency (up to 85%) by modulating the band slope and photocurrent generation through an external electric field. The vertical heterostructures allow for broad-area photocurrent generation, which is more efficient than lateral devices. The study also highlights the ability to control photocarrier generation, separation, and transport processes using an external electric field. The results show that the photocurrent can be modulated by adjusting the gate voltage, with the polarity and amplitude of the photocurrent being significantly influenced by the external field. The study further explores dual-gated devices, where both top and bottom gates can be used to modulate the photocurrent. The research demonstrates that the unique properties of vertical heterostructures, including the optical transparency of graphene and the partial electrostatic transparency of the material, enable efficient modulation of photocurrent generation. The study also compares the performance of vertical heterostructures with conventional photodiodes, showing that the vertical structures offer superior performance in terms of photocurrent efficiency and tunability. The findings have implications for the development of future photodetection and photovoltaic devices.