(AGENPARL) – LONDON (UNITED KINGDOM), mar 15 settembre 2020
Black phosphorus (BP) has emerged as a promising two-dimensional (2D) semiconductor for applications in electronics, optoelectronics, and energy storage. As is the case for many 2D materials, the fabrication of large-area BP thin films remains a considerable challenge. Here, we report the assembly of BP nanosheets into compact thin films using the Langmuir-Blodgett (LB) technique. The overlapping stacking between BP nanosheets is suppressed when the nanosheets are surrounded by fullerene C60 molecules due to physisorption. This allows for the fabrication of large-area BP films (20 mm × 18 mm) with a homogenous nanosheet distribution and negligible oxidation. The fabricated films show measurable absorption up to 2.3 µm. We use these films as active layers to demonstrate mm-sized BP heterojunction photodetectors with mA/W scale responsivities from the visible to the near-infrared. Photodetector internal quantum efficiencies at 660 nm and 808 nm are 5% and 1%, respectively.
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