• 제목/요약/키워드: Center-of-mass exciton

검색결과 2건 처리시간 0.017초

Two-dimensional Nature of Center-of-mass Excitons Confined in a Single CdMnTe/CdTe/CdMnTe Heterostructure

  • Lee, Woojin;Kim, Minwoo;Yang, Hanyi;Kyhm, Kwangseuk;Murayama, Akihiro;Kheng, Kuntheak;Mariette, Henri;Dang, Le Si
    • Current Optics and Photonics
    • /
    • 제2권6호
    • /
    • pp.589-594
    • /
    • 2018
  • We have investigated the dimensional nature of center-of-mass exciton confinement states in a CdMnTe/CdTe/CdMnTe heterostructure, where the CdTe well is too wide (144 nm) to confine both electrons and holes but able to confine whole excitons in the center-of-mass coordinate. Fine multiple photoluminescence spectra with a few meV separation were observed at 6 K. From the thickness dependence of the transition rate, they were attributed to even numbered center-of-mass exciton confinement states (N = 2, 4, 6, ${\cdots}$, 18). Dimensionality of the center-of-mass exciton confinement states was also investigated in terms of temperature dependence of radiative decay time. At low temperatures (${\leq}12K$), we found that the ground state excitons are likely localized possibly due to the barrier interface fluctuation, resulting in a constant decay time (~350 ps). With increased temperature (${\geq}12K$), localized excitons are thermally released, giving rise to a linear temperature dependence of radiative decay time as an evidence of two-dimensional nature.

인삼의 Polyacetylene 화합물 (Polyacetylene Compounds from Panax ginseng C.A. Meyer)

  • 심상철;장석구
    • 고려인삼학회:학술대회논문집
    • /
    • 고려인삼학회 1988년도 학술대회지
    • /
    • pp.122-128
    • /
    • 1988
  • 폴리아세칠랜계 화합물이 함유된 인삼의 석유 에텔 추출물은 시험관내 실험에서 Sarcoma 180, Walker carcinosarcoma 256, $L_{1210}leukemic$ lympocyte의 성장을 억제한다. 우리는 석유 ether 추출물로 부터 몇가지 포리아세틸렌계 화합물을 분리하여 화학구조를 밝혔다. UV, IR $^{1}H$ NMR, $^{13}C$ NMR, EI mass, CI mas, 원소분석과 산화 또는 산촉매 가수분해와 같은 화학적인 방법으로 얻어진 자료에 근거하여 이들은 heptadeca-1,9-dien-4,6-diyn-3-ol, hepatadeca-l-en-4.6-diyn-9,10-epoxy-3-ol 및 hepatadeca-1,8-dien-4,6-diyn-3,10-diol로 밝혀 졌다.

  • PDF