High-purity AlGaAs grown by molecular beam epitaxy using a superlattice buffer layer

High-purity Al0.3Ga0.7As is grown by molecular beam epitaxy at a high substrate temperature using a superlattice buffer layer in order to trap residual impurities. The unintentionally doped layer is p type with p < 5×1014 cm−3. Photoluminescence spectra at 10 K showed the strong bound-exciton emission to be 3.8 meV wide and extremely weak emission due to residual C and Si. Photoluminescence spectra of successively grown single-quantum wells with different widths demonstrate that residual C and Si are mainly trapped at the interface of the first-grown well.