Influence of order-domain size on the optical gain of AlGaInP laser structures

Ordered AlGaInP bulk layers and double quantum well laser structures have been grown by metalorganic vapor phase epitaxy at various growth temperatures. The dependence of the degree of ordering and the domain structure on the growth temperature and the aluminum content have been examined by photoluminescence excitation and transmission electron microscopy, respectively. We investigate the influence of these parameters on the optical gain and the threshold current density of ordered lasers. According to band structure calculations for the optical gain, CuPt_B-type ordering is supposed to enhance laser performance. However, up to now this has not been observed. We will show that the domain structure can be made responsible for the diminished laser performance of ordered structures. By changing the growth temperature within the epitaxial run, we introduce a method to separately control the degree of ordering and the domain size. By this manner, we were able to fabricate a highly ordered laser structure with improved performance.