Growth temperature dependence of optical properties of gas source MBE grown GaP/AlP short period superlattices

Growth temperature dependence of the optical properties of GaP/AlP superlattices (SLs) is studied. GaP/AlP SLs are grown on S-doped GaP (001) substrates at 600–660°C by gas source MBE (molecular beam epitaxy). Satellite peaks up to 4th order in the X-ray diffraction (XRD) rocking curve are clearly observed for all of the grown SLs. It is found that the 4.2 K PL (photoluminescence) intensity for the SLs increases by a factor of about 10 with increasing growth temperature from 600 to 640°C. Along with the PL intensity increase, the PL peak width (full width at half maximum) decreases from 15.5 to 9 meV. It is also found that the PL intensity variation with measuring temperature is slower for the 640°C grown SLs than for the 600°C grown SLs. At 18 K, the PL intensity for the 640°C grown SLs is about 660 times stronger than that for the 600°C grown SLs. The best results are obtained for the 640°C growth.