Absorption and Luminescence in Ultra-Thin Films of PbI₂

抄録

We have measured the absorption and luminescence spectra of the ultra-thin PbI₂ film evaporated on a cleaved KCl crystal at 100 K. The energy of the exciton absorption band is analyzed by the one-dimensional quantum well, but the exciton energies in the platelet crystals consisting of the two and three layers deviate from the simple theoretical values because of the too thin crystals. From the appearance of the broad luminescence band in the ultra-thin film, it is concluded that the free exciton level may become higher than that of the self-trapped exciton by the quantum well effect.