Size dependent effective band gap, optical absorption coefficients and refractive index changes in a wide ZnS/Zn1−xMgxS strained quantum well

• Published in: Physica. B, Condensed matter Condensed matter, 2012-07, Vol.407 (13), p.2578-2583
• Main Authors: Elangovan, P., John Peter, A.
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Excitation; Inclusions; Interband emission energy; Magnesium; Mathematical analysis; Nonlinearity; Optical absorption; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Phonons; Physics; Quantum well; Quantum wells; Zinc sulfides
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2012.03.073

Exciton binding energy of a confined heavy hole exciton is investigated in a Zn1−xMgxS/ZnS/Zn1−xMgxS single strained quantum well with the inclusion of size dependent dielectric function for various Mg content. The effects of interaction between the exciton and the longitudinal optical phonon are brought out. The effect of exciton is described by the effective potential between the electron and hole. The interband emission energy as a function of well width is calculated for various Mg concentration with and without the inclusion of dielectric confinement. Non-linear optical properties are carried out using the compact density matrix approach. The dependence of nonlinear optical processes on the well width is investigated for different Mg concentration. The linear, third order non-linear optical absorption coefficients values and the refractive index changes of the exciton are calculated for different concentration of magnesium content. The results show that the exciton binding energy is found to exceed LO phonon energy of ZnS for x>0.2 and the incorporation of magnesium ions and the effect of phonon have great influence on the optical properties of ZnS/Zn1−xMgxS quantum wells.