Properties of PbTe/EuTe short period superlattices and their application to laser diodes

Abstract

Short period superlattices (SPSLs) consisting of PbTe (E g=0.3eV) and EuTe (E g-2.0eV) were prepared on KCl (100) substrates by alternate growth of the PbTe (∼100 Å) and Eu (less than a few atomic layers) using a hot-wall technique. The structural properties were studied through x-ray diffraction and electron-probe micro analysis. The band gap of the SPSL, depending on average Eu (EuTe) composition, was determined by optical transmission measurement. It was found that the band gap of the SPSL of a small EuTe composition increases very sensitively with the EuTe composition, while that of a large EuTe composition depends only on the period length, resulting from the quantum size effect due to large band gap of EuTe (barrier). Results of magneto resistance measurements of the SPSL are also presented. A multiple quantum-well (MQW) laser was fabricated using the SPSL for barrier layers in the MQW active region and cladding layers. The laser operated up to 160 K (pulsed).