Improved Contact Properties in Violet Phosphorus via Bonding-Enabled Interfacing Engineering

Violet phosphorus (VP) has emerged as a promising two-dimensional material for photodetectors due to its excellent electronic and optical properties. However, the high contact resistance and uncontrollable Schottky barrier height at the metal-semiconductor interface limit the performance of VP-based device. Here, supported by Hartree potential analysis, we propose a bonding-enabled interfacing engineering by introducing a 20 nm indium (In) buffer layer. VP nanoflakes were prepared via multi-step mechanical exfoliation. An atomically sharp interface and partial ln–P bonding was observed at the VP/In interface, which enhanced interfacial coupling and improve photocarrier collection efficiency. The VP/In/Au photodetector exhibits enhanced photoresponse compared to VP/Au devices. This work provides a viable interface engineering strategy for contact optimization in VP-based optoelectronic devices.