Temperature dependent contactless electroreflectance study of intersubband transitions in a self-assembled InAs/InP (001) quantum dot structure

Contactless electroreflectance, in the range of 18<T<300 K, has been used to investigate a self-assembled InAs/InP (001) quantum dot (QD) structure fabricated by metalorganic vapor phase epitaxy. Signals have been observed from all the relevant portions of the sample including the QDs, wetting layer, InP cap layer, and/or substrate. The energies of the QD transitions are in good agreement with an envelope function calculation based on the physical parameters of the QDs as observed from transmission electron microscopy and other relevant parameters. The temperature dependence of the energies of all transitions has been fit using both the semiempirical Varshni and Bose-Einstein-like expressions. It was found that extracted Varshni and Bose-Einstein fitting parameters are in the range of those for most III-V materials, both bulk and quantum well. However, the temperature variation for the energy transitions in the QDs is somewhat larger that reported for bulk InAs. (C) 2003 American Institute of Physics.