Molecular beam epitaxial growth of IV-VI multiple quantum well structures on Si(111) and BaF2(111) and optical studies of epilayer heating

IV-VI semiconductor multiple quantum well (MQW) structures (PbSe/PbSrSe) we re grown on Si(111) and BaF2(111) substrates by molecular beam epitaxy. Str uctural and optical properties of the MQW structures have been studied usin g reflection high-energy electron diffraction, high resolution x-ray diffra ction (HRXRD), Fourier-transform infrared (FTIR) transmission, and midinfra red photoluminescence (PL). Numerous satellite diffraction peaks and narrow linewidths of the HRXRD rocking curves indicate the high crystalline quali ty of the structures grown on both Si and BaF2. Longitudinal and oblique va lley subband transitions without superposed interference fringes were obser ved in FTIR differential transmission spectra. Continuous wave midinfrared photoluminescence was also observed from both sets of samples. Comparison o f FTIR and PL spectra allows determination of localized epilayer heating in the MQW samples due to optical pumping. For a typical laser pumping power of 9.1 W/cm(2) the heating in a MQW layer on Si(111) was 70 degreesC, while the amount of heating for a MQW layer on lower thermal conductivity BaF2 w as 83 degreesC. (C) 2001 American Vacuum Society.