Temperature dependence of the threshold current density and external differential quantum efficiency of semiconductor lasers (λ = 900–920 nm)

The temperature dependences of the emission characteristics of semiconductor lasers based on asymmetric separate-confinement heterostructures with a broadened waveguide fabricated by metalorganic chemical vapor deposition (radiation wavelength λ = 900–920 nm) have been investigated. It is found that an increase in the energy depth and number of quantum wells (QWs) in the active region makes it possible to increase the temperature stability of the threshold current density and the differential quantum efficiency of semiconductor lasers on the basis of these structures. A temperature stability of threshold current density with a characteristic parameter T0 = 290 K has been obtained in lasers based on a heterostructure with four QWs. It is experimentally shown that the laser parameters are stabilized due to the decrease in the threshold current density and threshold carrier density in the QWs of the active region. It is also demonstrated that, when the carrier concentration in these QWs reaches a certain value, the temperature stability of the threshold current density and differential quantum efficiency sharply decreases.