DEPENDENCE OF THE INJECTION CURRENT AT LASING THRESHOLD ON STRUCTURE AND LOSSES IN ALGAN GAN LASERS/

We present calculations of the threshold current densities, J(th), in AlGaN/GaN double heterostructure lasers for different active region th ickness, losses, and cavity lengths. Two-dimensional (2-D) numerical s imulations indicate that for a 100-mu m long cavity, a 0.1-mu m thick active region gives the lowest J(th) when only mirror losses are prese nt. As losses increase, the minimum moves to thicker active regions. J (th) versus optical loss plots demonstrate that with the high optical losses in the materials grown, it will be easier to induce lasing in t hick active region structures. Results for AlGaAs/GaAs lasers presente d for comparison, demonstrate that AlGaN/GaN lasers have higher J(th) unless the active region is very thin.