TEMPERATURE-DEPENDENCE OF THE THRESHOLD CURRENT FOR ALGAAS LASERS GROWN BY LOW-TEMPERATURE LPE

In the present work we study the temperature dependence of the threshold current density J(th) in straight separate confinement heterostructure (SCH) lasers. The laser structures were grown by the low temperature liquid phase epitaxy (LT-LPE) technique. The threshold current of the devices was measured in a wide temperature interval (77-350 K) for conventional and quantum well (QW) lasers. In order to have a better characterization of the laser diodes and understanding of the results, theoretical estimations of the temperature dependence of J(th) were performed. The theory takes into account three loss mechanisms: leakage current, non-radiative recombination from the L and X conduction band minima of the active layer material and Auger recombination. The experimental results fit quite well the theoretical predictions. Moreover, it will be shown that the mayor influencing factor in the threshold current density-temperature behavior is the leakage current. The relatively high. values of the characteristic temperature To obtained, prove that LT-LPE technique is a suitable one for the performance of laser diodes with a good thermal stability.