(Dark Line Defects, Bright Line Lasers)‐Microscopic Studies of Single‐Shot Lasing in CdSe Quantum Wells

A preliminary report on single quantum well (SQW) lasers of CdSe grown by metalorganic vapour phase epitaxy (MOVPE) in a matrix of ZnSe is presented. The total device thickness is 3 μm. The quantum wells are „ultrathin”︁ in the range from 0.5 to 2 monolayers (ML). The time‐integrated spectra of spontaneous emission from the top surface of as‐grown samples are compared with spontaneous and stimulated edge emission from cleaved laser cavities. Such temporally and spatially integrated spectra are contrasted with single‐shot laser spectra obtained by adapting a 1 m single monochromator to operate as a videospectrograph. In addition to „hidden”︁ mode structure, the spectrograms reveal the strongly heterogeneous character of laser emission from these samples: bright lines that indicate materials of good quality are found adjacent to dark lines where the emission is weak or absent.