Performance Analysis of MoS 2 /h-BN/Graphene Photodetector: A Numerical Modelling Approach

Photodetector is a device that detects light and converts the measurable electrical signal in terms of voltage and current. Recently, two-dimensional (2D) materials such as molybdenum disulfide (MoS 2 ) has been extensively studied for photodetection application due to its superior optical properties in detecting light at the visible range. However, the poor carrier mobility in MoS 2 limits its performances in terms of responsivity and specific detectivity. This issue is tackled by hybridization of MoS 2 with other 2D materials such as graphene, which has excellent electrical properties. In this work, a photodetector with MoS 2 /h-BN/graphene heterostructure was numerically modelled using Silvaco Atlas, utilizing the Fowler-Nordheim and Direct Quantum Tunneling carrier mobility models. The functionality of the device was validated and confirmed based on the I-V characteristics, where the current upon illumination of 405 nm wavelength, is higher than the initial dark current with an on/off ratio of 1010 at 6 V. The structural analysis showed that the photogeneration rate increased from 24.2, 24.9 and 25.2 pairs/cm3s as the optical light intensity was increased from 10, 50 to 100 W/cm2, respectively due to increment in numbers of photons which contribute to higher photogenerated carriers. This preliminary framework will be extended for further validation in terms of dark current and illuminated current before improving the performances of this device with dimension tailoring and plasmonic coupling.