Effects of nonradiative recombination on the temperature characteristics of threshold current density in 670 nm GaInAsP-AlGaAs visible lasers

The effect of nonradiative recombinations on the temperature characteristics of threshold in 670 nm GaInAsP lasers are investigated with theoretical calculations. Lasers with different Al contents (X _Al) and p-type doping carrier concentrations of the AlGaAs cladding layers were fabricated in order to evaluate the threshold current densities (J_th) and the temperature characteristics of J_th. The dependence of J_th on the active layer thickness was also evaluated. By subtracting the calculated pure radiative recombination component of J_th from the experimental J _th values, the nonradiative recombination current densities were obtained as a function of inverse temperature. The thermal activation energies were evaluated for different ΔE_g . It was found that the nonradiative recombinations were governed by the heterobarrier heights. The increase of J_th with decreasing X_Al was explained theoretically in terms of the carrier leakage over heterobarriers. It is concluded that the carrier leakage components are the main nonradiative recombination processes in these lasers