Semiconductor lasers and photodiodes for gas analysis in the spectral range 1.8-2.5 um

摘要

Semiconductor lasers and photodiodes for the 1.8 - 2.5 $mu@m spectral range are described, which can be used in gas analysis systems. In spite of the fact that the strongest absorption lines of many gaseous substances are concentrated at longer wavelength, the spectral range in the vicinity of 2 mm seems to be more promising because powerful light sources and high efficiency photodetectors operating at room temperature can be developed, in contrast to the wavelengths exceeding 3 $mu@m. Characteristics of several lasers are presented. Among them are pulsed lasers with an output optical power reaching 1 W and low threshold single mode lasers. The photodiodes possess high quantum efficiency (0.6 without antireflection coating) and a high response speed (0.5 ns at reverse bias of several volts). The quaternary solid solutions GaInSbAs and GaAlSbAs lattice matched to GaSb substrates were used for fabrication of all the structures. The first material was used in active regions of the devices and the second one in wide gap layers - emitters in the lasers and window layers of the photodiodes. The structures were grown by liquid phase epitaxy.