Y. Kawakami et al., EFFECTS OF HIGH-EXCITATION ON LOCALIZED EXCITONS IN CUBIC ZNCDS LATTICE-MATCHED TO GAAS, Journal of crystal growth, 159(1-4), 1996, pp. 830-834
Effects of high excitation on localized excitons have been studied in
cubic Zn0.42Cd0.58S lattice-matched to GaAs. The time-integrated photo
luminescence (PL) spectrum at 2 K under weak excitation conditions (0.
025 mu J/cm(2)) was composed of a single emission peaking at 2.863 eV
and its LO-phonon replica, The linewidth of the main peak was 18.5 meV
. With increasing excitation energy density (I-ex), the spectra broade
ned, especially on the lower energy side and a small shoulder appeared
at about 2.85 eV for I-ex greater than or similar to 2 mu J/cm(2). In
order to study the detailed mechanism, the nonlinear luminescence com
ponent was studied by the population mixing technique. The positive si
gnals were detected on the lower energy side (2.85 eV) at an I-ex valu
e in the range between 1.8 and 2.9 mu J/cm(2). This nonlinear componen
t was attributed to localized excitonic molecules.