H. Asahi et al., GAS-SOURCE MOLECULAR-BEAM EPITAXY GROWTH OF GAP ALP SHORT-PERIOD SUPERLATTICES/, Journal of crystal growth, 136(1-4), 1994, pp. 268-272
GaP/AlP short period superlattices (SLs) are grown on GaP substrates b
y gas source molecular beam epitaxy (MBE). Strong photoluminescence is
observed in the green-to-yellow wavelength range at 4.2 K. Photolumin
escence and electroreflectance spectra are in good agreement with the
theoretical predictions for the formation of the zone-folded direct ba
nd gap. The refractive indices of the SLs are larger than those of bul
k GaP, AlP and AlGaP, indicating the possibility of formation of laser
diode structures using GaP/AlP SL as an active layer. By using Be as
a p-type dopant source, a hole concentration of as high as 1.5 X 10(19
) CM-3 is easily obtained in GaP. It is also shown that the interface
and optical properties of SLs are improved by gas source migration enh
anced epitaxy.