MBE growth and characterization of IV-VI semiconductor thin-film structures on (1Â 1Â 0) BaF2 substrates

PbSe thin film and PbSe/PbSrSe multiple quantum well (MQW) structures were successfully grown on (1 1 0) BaF2 substrates by molecular beam epitaxy. The average linewidth of the rocking curve from high-resolution X-ray diffraction measurements of the (2 2 0) reflection for the PbSe thin film was 60 arcsec, which indicates high crystalline quality. The dislocation density estimated from the rocking curve was 1×107 cm−2. Strong photoluminescence (PL) of the MQW structure at room temperature was observed. This PL signal was two times larger than those measured from a duplicate structure grown at the same time on a (1 1 1) BaF2 substrate. The energy bandgap of (1 1 0) PbSe follows the same temperature dependence as [1 0 0]- and [1 1 1]-orientated PbSe.