Modified Hot Plate Method for Synthesizing MoO₃ Nanoplates

Molybdenum trioxide (MoO₃) with layered structures adopts exotic physical features, which has evoked an extensive interest in electronic and photoelectronic devices. Here, we report a low-cost, simple-handle, atmospheric-pressure, and rapid-synthesis technique for growing large-scale MoO₃ crystals, i.e., a modified hot plate method. The growth rate and morphology of the MoO₃ crystals were well controlled by changing source temperatures and substrates. Complementary measurements, including optical microscope, atomic force microscope, X-ray diffraction, Raman spectroscope, and scanning near-field optical microscope, were used to investigate the structural and physical properties. The results reveal that large-scale MoO₃ crystals with well-defined crystallinity have been obtained. Meanwhile, surface hyperbolic phonon polaritons on as-prepared MoO₃ crystal planes have also been observed, which may provide an attractive insight into nanoelectronic and nanophotonic devices.