Photoluminescence Investigation of Nano-flakes of MnPS₃Antiferromagnet

Transition metal thiophosphates MPS₃ (M=Mn, Fe, Ni) are considered as promising platform for investigating novel magneto-optical phenomena for applications in spintronics. In particular, MnPS₃ is interesting because the photoluminescence (PL) from micrometer-sized exfoliated flakes was reported to have strong interaction with the Néel ordered state (T_N = 78K) that persists down to monolayer thickness allowing to tune the optical properties by forming different heterostructures. Here we investigate the optical properties of crystalline nanometer-sized flakes of MnPS₃. AFM characterization shows thickness of the flakes ranging from few to tens of nm and the lateral size about tens of nm. In contrast to PL emission from micrometer-sized flakes which were reported to have broader linewidth around 100nm [1], we observe sharp emission peaks for nano-flakes with the linewidth lesser than 2 nm. We also observe the emission peaks varies from one nano-flake to another ranging from 575nm to 630 nm whereas the micro-flakes have fixed peaks at 566 nm and 941 nm. In addition, our nano-flakes also exhibit strong degree of linear polarization, blinking and spectral diffusion characteristics.