Photoreflectance and photoluminescence studies of epitaxial InGaAs quantum rods grown with As2 and As4 sources

Photoreflectance spectroscopy and photoluminescence (PL) have been used to explore the optical properties and electronic structure of InGaAs quantum rods (QRs) grown by molecular beam epitaxy. Different As sources — As2 and As4 — were used during epitaxial growth in order to evaluate their effect on the optical properties of the nanostructures. Spectral features associated with interband optical transitions taking place in the QR and the surrounding quantum well (QW) regions are examined. A redshift of the QR- and a blueshift of the QW-related optical transitions, along with a significant increase in PL intensity, have been observed if an As4 source is used. These changes in optical properties are mainly attributed to quantum confinement effects related to a variation of indium content in the QR and QW regions.