Full Vertical 2D TMDs/Graphene vdW Heterostructure NIR Photodetector for Fast Response

In the era of big data, where data volumes are increasing exponentially, data processing speed directly influences the efficiency of large-scale data transmission. It is also crucial for sensors receiving the information to have fast response times. Currently, most industrial Near Infrared Photodetectors (NIR PDs) rely on compound semiconductors like InGaAs and GaAs, which present cost challenges due to complex and expensive processes. As an alternative, 2D Transition Metal Dichalcogenides (TMDs), which are somewhat tolerant of lattice mismatch and relatively low-cost, have been extensively studied. Conventional TMDs-based PDs have been reported to exhibit lateral¹ and semi-vertical² structures. However, these PDs demonstrate relatively slower response times^2,3 due to long carrier pathways, leading to increased parasitic resistance. To address this, we propose a novel full-vertical 2D TMDs/graphene van der Waals heterostructure for fast response. As the thickness of MoTe₂ increases, more MoTe₂ interacts with photons, improving the photoresponse. On the other hand, thicker MoTe₂ extends the carrier pathways, which directly affects the response time. Therefore, we have investigated the trade-off between photoresponse and response time by adjusting the thickness of MoTe₂. By optimizing this structure, we can minimize the carrier transport pathways, which apply the maximum electric field efficiently. As a result, we achieved a device with both fast response times and high photoresponse. We anticipate that this innovative design will inspire further research into 2D material-based photodetectors.<br/><br/>Reference:<br/>[1] ACS omega, 7(12), 10049-10055. 2022.<br/>[2] ACS Photonics, 8(9), 2650-2658. 2021.<br/>[3] ACS Applied Materials & Interfaces, 16(28), 36609-36619. 2024.