OPTICAL-PROPERTIES OF GAP/ALP SHORT-PERIOD SUPERLATTICES GROWN BY GAS SOURCE MOLECULAR-BEAM EPITAXY

Optical properties of (GaP)m/(AlP)n superlattices (SLs), with m+n=14, grown on GaP(001) by gas source molecular beam epitaxy have been studied by photoluminescence (PL), electroreflectance (ER), and optical reflectance. The dependence of the PL peak energies and the relative intensity on the monolayer number of AlP is in agreement with those theoretically predicted for the case of type II band alignment of GaP/AlP SLs. The refractive index of GaP/AlP SLs has been studied for the first time and compared with that of an AlGaP alloy. The refractive index calculated for an AlGaP alloy using a single-effective-oscillator model is consistent with the experimentally obtained results.