Investigation of the quantum well width on the size effect of PbSe/ZnSe multiple quantum well structures by non-epitaxial growth

Abstract

• PbSe/ZnSe multiple quantum well structures by non-epitaxial growth. • Well-ordered periodicity of 2D layers of PbSe was confirmed through TEM. • Evaluation of PbSe nanocrystal phase was observed about its critical layer thickness. • Enhanced optical absorption with various PbSe quantum well thickness. • Quantum confinement from shift in optical phonon modes of Raman scattering. PbSe/ZnSe multiple quantum well (MQW) structures were prepared by non-epitaxial growth to investigate the impact of quantum well width ( L z ) on the size effect. X-ray diffraction studies revealed the evaluation of PbSe nanocrystals phase about its critical layer thickness. Well-ordered and periodic structure of the MQW was confirmed through TEM and its interface morphology of L z = 2.5 and 10 nm were studied. The discrete linear resonances in the absorption spectra and the corresponding blue shift reflect the quantum confinement effect. The effective QW band gap energies calculated from the infinite well approximation is compared to the experimentally observed values. Shift in longitudinal optical phonon from Raman scattering indicates stress induced size effect in PbSe/ZnSe MQW structures.