Excitation intensity dependence of up-converted emission in ZnSe-ZnTe superlattice grown by MBE

The photoluminescence (PL) spectra of the type II ZnSe-ZnTe superlattices with dual-subband structures have two emission peaks. The PL peak at the higher energy side appears by the excitation even with the light, with the middle energy between the PL peaks. The emission energy of the up-converted light shows dependence similar to the case of direct excitation (high-energy excitation) on the excitation intensity. The emission energy increases with increase in the excitation intensity. The up-converted and the direct excited emissions are due to the same state in the superlattice.