Waveguide properties of gallium, aluminum, and indium nitride heterostructures

Abstract

The waveguide properties of double heterostructures constructed from nitrides of group-III elements are investigated. It is established that a maximum 8–10% AlN is sufficient (for limiting the optical mode inside the active region) in the solid solution of the wide-gap layer. The influence of light absorption in the wide-gap layers on the threshold current density of heterostructure lasers is taken into account. This form of light absorption is probably a decisive factor for heterostructures utilizing III-nitrides. A threshold current density at levels of the order of 10 kA/cm2 is expected for lasers utilizing such structures. Because of strong light absorption in the waveguide layer, the threshold current density for lasers with solitary quantum wells cannot be expected to be any lower than that of conventional double-heterostructure lasers. The threshold current density can be lowered to a few kA/cm2 in the case of lasers with a large number of quantum wells.