4:00 PM - 6:00 PM
▼ [10p-PB5-43] Optical Spectroscopy of Artificial Hetero-structure of Monolayer MoSe2 and Manganese Oxide
Keywords:two-dimensional semiconductor, manganese oxide, artificial hetero-structure
Due to the direct bandgap coupled with spin-valley degree of freedoms, two-dimensional (2D) semiconducting transition metal dichalcogenides have attracted much attention. Recently, the artificial hetero-structures based on monolayer transition metal dichalcogenides and various 2D materials such as insulators, ferromagnetic semiconductors and metals were extensively studied. Among them, a strongly correlated electron system of manganese oxides exhibits unique magnetic and carrier transport properties. Hence, it is interesting to explore excitonic physics and applications in the artificial hetero-structure using manganese oxides. In this work, we studied artificial hetero-structure of monolayer (1L) MoSe2 and manganese oxide (La1.2Sr1.8Mn2O7). The La1.2Sr1.8Mn2O7 is a ferromagnetic metal below TC = 126 K, and shows large negative magnetoresistance2. The temperature dependence of photoluminescence (PL) spectra of hetero-structure (1L MoSe2La1.2Sr1.8Mn2O7) and reference (1L-MoSe2SiO2) were measured. Figure 1(a) shows the PL spectra of 1L-MoSe2 in the hetero- and reference-structure at 10 K. In both spectra, the two-emission peaks from exciton (X) and charged exciton, trion (X-) were observed. Figure 1(b) shows the temperature dependence of PL intensity ratio of X-and X (IX/-IX) in the hetero-structure and reference. We observed that significant difference of PL intensity ratio of X- and X in the hetero-structure and reference, which suggests that the doped carrier density of 1L-MoSe2 is much different in the hetero-structure and reference because the PL intensity of X- reflects the doped carrier density. We will also discuss the excited state dynamics within the framework of an exciton and a trion.