CVD growth of layered Cr2O3 hexagonal flakes for optoelectronic applications

Highlights: • Cr₂O₃ has a layered structure in the corundum structure phase. • Layered 2D-Cr₂O₃ hexagonal flakes were synthesized by CVD method. • DFT calculations were used to predict the spin-phonon interaction. • Polarized Raman study predicted anti-ferromagnetic spin ordering in Cr₂O₃. • Photo-response was measured for their use in spintronic devices. Chromium (III) oxide (Cr₂O₃) is a unique material which possesses a layered structure in the corundum structure phase, quite similar to the graphene and other transition metal dichalcogenides (TMDCs). Systematically, layered 2D-Cr₂O₃ hexagonal flakes were synthesized by chemical vapor deposition (CVD) method with Iodine as an assisting material. Under the controlled conditions (temperature, N₂:H₂ in carrier gas, etc), Iodine is playing a key role in transforming the crystal structure into hexagonal phase and grows in the form of layers. Incident light polarization dependent Raman spectroscopy was employed to see the coupling of in-plane E_g mode with spin to predict the anti-ferromagnetic ordering of spin in Cr₂O₃ hexagonal flake. Due to layer stacking and ordering, strong feature of creation of magnon states has been observed in photoluminescence (PL) spectroscopy. Finally, photo-detector response was measured to test the stability and reliability of the as-grown flakes for their use in spintronic devices.