Abstract
? 2022 Elsevier B.V.Recently, BiI3 was discovered as a promising 2D semiconductor materials for photovoltaic and photodetector device, due to its suitable bandgap, high optical absorption coefficient, excellent electron mobility, and low carrier concentration. However, as so far, only the CVD/PVD grown BiI3 nanoflakes/films have been reported. Here, we firstly synthesized the O-doped BiI3 (OBI) bulk crystals via chemical vapor transport (CVT) method, and then systematically studied the electrical and optoelectronic properties of exfoliated multi-layer OBI nanoflakes. Back-gated field-effect transistor fabricated on the multi-layer OBI nanoflakes with van der Waals (vdW) bottom electrode contact exhibited n-type semiconducting characteristics. In addition, exfoliated multi-layer OBI based photodetector demonstrates an excellent photoresponse with good reproducibility at room-temperature for visible wavelengths, including a high photo-to-dark current ratio (2.16 ×104), a remarkable photoresponsivity (850 mA W?1), a fast response speed (rise/decay time of 3.2/2.9 ms), and a high specific detectivity (9.85 ×1012 Jones), which is favored by the ultralow dark current (～30 fA). These results indicated that the OBI crystals have great potential for future applications in highly sensitive and ultrafast visible-light photodetector.
NSTL
Elsevier