Ordered AlGaInP bulk layers and double quantum well laser structures h
ave been grown by metalorganic vapor phase epitaxy at various growth t
emperatures. The dependence of the degree of ordering and the domain s
tructure on the growth temperature and the aluminum content have been
examined by photoluminescence excitation and transmission electron mic
roscopy, respectively. We investigate the influence of these parameter
s on the optical gain and the threshold current density of ordered las
ers. According to band structure calculations for the optical gain, Cu
PtB-type ordering is supposed to enhance laser performance. However, u
p to now this has not been observed. We will show that the domain stru
cture can be made responsible for the diminished laser performance of
ordered Structures. By changing the growth temperature within the epit
axial run, we introduce a method to separately control the degree of o
rdering and the domain size. By this manner, we were able to fabricate
a highly ordered laser structure with improved performance.