Observation of quantum-size effects in optical transmission spectra of PbTe/Pb1−<i>x</i>Eu<i>x</i>Te superlattices

Abstract

Optical transmission spectra of PbTe/Pb1−xEuxTe (x=0.05) superlattices were measured at 300 K. The superlattices were prepared on thick Pb1−xEuxTe buffers grown on KCl (100) substrates using the hot wall epitaxy technique. Clear steplike absorptions corresponding to the interband electron transitions between subbands (n=1,2,3 to n=1,2,3) were observed for the first time for the PbTe/Pb1−xEuxTe superlattice. The experimental absorption edges agreed very well with theoretical ones calculated assuming the conduction-band offset is equal to that of the valence band.