DYNAMICS OF FREE EXCITON LUMINESCENCE IN CDXZN1-XTE/ZNTE QUANTUM-WELLS

In this paper we show that CdxZn1-xTe/ZnTe quantum wells can be grown to very high quality. These materials exhibit strong sharp free exciton resonances in absorption and emission, which are inhomogeneously broadened by alloy fluctuations and homogeneously broadened by LO-phonon interactions. At low intensities their emission spectra show characteristic sharp lines superimposed on the background luminescence. These sharp lines are attributed to the relaxation of hot excitons created by LO-phonon assisted absorption. The decay of the photoluminescence under pulsed excitation was measured with picosecond resolution. The luminescence lifetime increases from 60 ps on the high energy side of the line to 200 ps on the low energy side. These lifetimes are shorter than those reported in similar materials. © 1989.