Microbeam Laser Characterization in MnPS ₃ (MnPSe ₃ )–WS ₂ Wide-Bandgap Semiconductor Heterojunction Photodetectors

We present a holistic evaluation into the optoelectronic performance of photodetectors fabricated from pristine multilayer MnPS 3, MnPSe 3, alongside MnPS 3 –WS 2 and MnPSe 3 –WS 2 heterojunctions. The measurements were performed using a broad laser beam of substantial spatial coverage (∼100 μm diameter), across various wavelengths (375 nm, 405 nm, 532 nm, 660 nm) under ambient conditions. We detailed each device’s bandwidth, responsivity, external quantum efficiency, noise equivalent power (NEP), and detectivity ( D *) under selected scenarios. MnPS 3 devices showed heightened sensitivity to UV light, while MnPSe 3 detectors exhibited a broad detection range. Moreover, we observe a considerable leap in the MnPS 3 –WS 2 heterojunction photodetector’s responsivity (422 times higher) and detectivity (129 times higher) in comparison to pristine multilayer MnPS 3 . Employing a localized incident focused UV laser spot (∼1 μm diameter), we examine the photocurrent dynamics in detail, as the laser transverses across the lateral dimension of the heterojunction. A decreasing trend of the photoresponse was observed, when transiting from MnPS 3 to the heterojunction and toward WS 2, elucidating carrier extraction and storage mechanism across the various laser-illuminated positions.