The scaling of the effective band gaps in indium-arsenide quantum dots and wires

Colloidal InAs quantum wires having diameters in the range of 5-57 nm and narrow diameter distributions are grown from Bi nanoparticles by the solution-liquid-solid (SLS) mechanism. The diameter dependence of the effective band gaps (ΔE_gs) in the wires is determined from photoluminescence spectra and compared to the experimental results for InAs quantum dots and rods and to the predictions of various theoretical models. The ΔE_g values for InAs quantum dots and wires are found to scale linearly with inverse diameter (d^-1), whereas the simplest confinement models predict that ΔE_g should scale with inverse-square diameter (d^-2). The difference in the observed and predicted scaling dimension is attributed to conduction-band nonparabolicity induced by strong valence-band - conduction-band coupling in the narrow-gap InAs semiconductor.