Lifetimes of Singlet and Triplet Excitons in β-ZnP_2

概要

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Tetaaporal behaviors of' the radiative recottabit'uatiot'x of excitotts have been studied in J-ZnPzby ttsing picosecond laser ptrlses at 2 K. Under itaterb?ttud excitation xvitla Efc, tl'te singletexciton ltttninescence decays with two exponential cornponents, 250 ps and 1.25 ns. Tlae lattervaltre is reasonable for the alloxved exciton transition. Tlae trijclet exciton Itrtniraescence decaysalso with two exporaential cotnponents, 150 ps arad abotrt 2.05 ras. These decay titnes of tlaetriplet ltrminescence are strrjcrisingly short, becatuse the trijclet exciton is ozaly weakly allowedand expected to laave a lorag lifetitne. The relative intensity of' the fatst co?nporaent of' the tripletItrminescence decreases, 218 tlae excit?ttion density decreases. Tlais coraaponent is attributed to thefornuation of the excitonic rnolecttle vi?t collision of txvc>triplet excitons. Tlae decay Litre of the sloxvconaaponettt does not change largely with the excitatiota power, strggestir?g effectixre nonradiativedecay processes. When the exciton is created in a btulk of tlae crystal trnder excitation into thetriplet exciton band with Efb, the trijclet ltruaainescetuce shoxvs a btrild-trp coraapot'xent, for xvluichexciton diffusion tneclaat'xisna is suggested. The de-excitatioua processes of' the triplet exciton arebriefly discussed.
社団法人日本物理学会の論文
1999-06-15