Pure-Ge/Sishortperiodsuperlattice(SPS)grownbygassourceMBE(GSMBE)isstudiedbyphotoluminescencespectroscopyandRamanscatteringspectroscopy.AnabnormalbandinphotoluminescenceisfoundinanintermediaterangeofLsibetween1.9nm-2.9nmforsampleswithLgefixedat1.5ml.Incontrasttoapure-Ge/Siquantumwell,theenergyofthebandshowsred-shiftasLsiincreases.RamanscatteringshowsthatSi-SivibrationrelatedRamanshiftreachesaminimumforsampleswithstrongestPLintensityoftheabnormalband.Itisthereforeconcludedthattheabnormalbandisrelatedwithstrainrelaxationprocess.
