[19p-436-1~17] 13.2 Exploratory Materials, Physical Properties, Devices

△ [19p-436-11] Green emission from SrHfS₃ with perovskite structure at room temperature

〇Kota Hanzawa¹, Soshi Iimura¹, Hidenori Hiramatsu^1,2, Hideo Hosono^1,2 (1.MSL, Tokyo Tech, 2.MCES, Tokyo Tech)

Keywords:Semiconductors, Optical property, Sulfide

To realize next-generation device applications, the most difficult challenge is to develop blight green-emitting sources. Thus we focus on exciton due to its highly efficient emission. High ionicity is a key factor to obtain high exciton binding energy; whereas, deep CBM and shallow VBM are also required to achieve n- and p-type dopings. However, the d orbitals of high ionic elements such as early transition metals (eTM) usually form a shallow CBM level. Recently, to realize eTM-based semiconductors, we proposed to create non-bonding state, which forms a deeper energy level, in high symmetry crystal structure. We selected sulfide-perovskite SrHfS₃ with the CBM and VBM, which consist of nearly non-bonding state of Hf 5d and S 3p orbitals, as indicated via DFT calculation.
The optical bandgap and photoluminescence (PL) of obtained polycrystalline SrHfS₃ was 2.3 eV and exhibited intense green emission. Note that the emitting light can be seen by human eyes even at RT. PL arising from defects was not observed, suggesting that concentration of deep defects is quite low. These results indicate that SrHfS₃ is a promising candidate for a green-emitting semiconductor.