EMISSION WAVELENGTH AND CAVITY DESIGN DEPENDENCE OF LASER BEHAVIOR INHGCDTE HETEROSTRUCTURES

Optical gain and laser emission have been studied in molecular beam ep itaxy grown HgCdTe heterostructures emitting in the 1.9-3.5 mu m wavel ength range. Laser emission is observed up to room-temperature for sam ples emitting in the 1.9-2.5 mu m range. The use of quantum wells and of a graded index in the barriers has allowed a significant reduction of the laser thresholds as compared to a separate confinement heterost ructure of similar composition: thresholds as low as 53 W cm(-2) at 20 K and 295 W cm(-2) at 100 K have been obtained. As the emission wavel ength increases, the characteristic temperature T-0 observed at high t emperature becomes less favourable: 63, 45 and 30 K for the 1.9, 2.5 a nd 3.5 mu m emitting samples, respectively. For this last sample, lase r emission has been observed only up to 150 K. This degradation of the lasing condition is interpreted as being due to the Auger effect, whi ch becomes increasingly important as the band gap decreases.