Temperature dependence of excitonic properties of (111)B InGaAs/GaAs piezoelectric and pyroelectric multiquantum wells

We report the comprehensive study on the temperature dependence of excitonic properties for an InGaAs/GaAs p-i-n multiquantum well structure grown on a (111)B GaAs substrate by molecular-beam epitaxy using photoreflectance spectroscopy, in which the pyroelectric effect (temperature dependence of piezoelectric field) is taken into account. The temperature dependence of the confined transition energies was investigated in terms of a Varshni's semiempirical equation and a Bose-Einstein expression to analyze the excitonic properties. We also determined the optical-phonon energy and strength of electron-phonon coupling for the < 111 > crystallographic directions of this material system, as well as the interface roughness from an analysis of the temperature dependence of PR broadening parameters. (C) 2009 American Institute of Physics. [DOI:10.1063/1.3182799]