PHOTOPUMPED LASING PROPERTIES IN ZNCDSE-ZNSSE MULTIPLE-QUANTUM WELLS

Photopumped lasing properties in a temperature range between 4.2 K and room temperature in a Zn0.83Cd0.17Se-ZnS0.10Se0.90 multiple quantum well structure prepared by metalorganic molecular beam epitaxy (MOMBE) have been investigated. Photoluminescence (PL) under low excitation, absorption and optical gain as well as the stimulated emission spectra have been systematically compared. It was estimated that the value of the Stokes shift between PL and absorption peak energies was as small as 5 meV at 4.2 K. However, the shift was hardly observed above 150 K. Low threshold excitation intensity for the lasing and lack of any difference in the values of full width at half maximum (FWHM) between the spectra of the optical gain and the heavy hole (HH) exciton absorption coefficient indicate that the exciton is related to the lasing mechanism at a temperature lower than approximately 150 K.