Electro-Optical Analysis of Tungsten Diselenide(WSe₂) Monolayer Laser-induced Homojunction Photodetector

WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, a member of the transition metal dichalcogenides (TMDs) family, exhibits excellent properties such as mechanical flexibility and strength, tunable bandgap, high carrier mobility, and strong light-matter interaction, making it an ideal candidate for photodetection applications. The properties of WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> can be manipulated by changing the number of layers, which allows for the engineering of devices tailored for specific wavelengths and types of light. We aim to explore these properties through comprehensive modeling and experimental validation to achieve high-performance photodetectors. The methodology involves MATLAB simulation modeling of the electronic and optical analysis of WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>-based homojunction photodetectors. Scharfetter-Gummel Scheme is employed to predict device performance, followed by experimental characterizations to validate the simulation results. This research demonstrates that our modeled WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> homojunction photodetector exhibits low dark current density in the picoampere range. The simulation results, validated by experimental data, show excellent agreement. The device has a low dark current of around 200 fA. In the optical analysis of the WSe<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> photodetector, we got peak normalized responsivity at a wavelength of 549 nm which shows good agreement with experimental data. Furthermore, the peak quantum efficiency was found to be at 2.34% which is in close agreement with the 2.6% peak quantum efficiency found in the experimental data.