[8p-Z08-1~8] 10.4 半導体スピントロニクス・超伝導・強相関

[8p-Z08-2] Excitation energy dependence of valley polarization in monolayer WS₂ treated by organic acid

〇(M1)木村 俊¹、朝倉 永人¹、アレクサンダーウェバー ジャック²、タノ アレロ³、ブレッチャー ホープ³、ステファン ホフマン²、ラオ アクシャイ^3,4、輕部 修太郎^1,5、新田 淳作^1,5,6、好田 誠^1,5,6,7 (1.東北大工、2.ケンブリッジ大マテ、3.キャベンディッシュ研、4.ケンブリッジ大化、5.東北大CSRN、6.東北大CSIS、7.東北大FRiD)

キーワード：spintronics, valley, TMDC

Recently, the valley polarization of exciton and stabilization of trion emission in addition to the exciton has been observed in monolayer WS₂ treated by organic acid like oleic acid(OA). In this research, we investigated the excitation energy dependence of the valley polarization for trion in OA-treated monolayer WS₂ by the photoluminescence (PL) measurement. We observed two different peaks in the PL spectra which are originated from singlet and triplet trions. By increasing the excitation laser energy, singlet trion intensity is reduced around 2.17eV. On the other hand, the degree of valley polarization for singlet trion is slightly increased with the excitation energy. Moreover, triplet trion shows much higher valley polarization than that of singlet trion, which is promising for using triplet trion as highly efficient spin polarized emitter. Further analysis to clarify the origin of higher valley polarization n triplet trion will be discussed in the presentation.