SIZE DEPENDENCE OF STRAIN RELAXATION AND LATERAL QUANTIZATION IN DEEPETCHED CDXZN1-XSE ZNSE QUANTUM WIRES/

A systematic experimental and theoretical analysis of the lateral size and composition dependence of strain release and lateral quantization in etched CdxZn1-xSe/ZnSe quantum wires is presented. Wires with late ral structure sizes down to 14 nm were realized by electron beam litho graphy and wet chemical etching and characterized by photoluminescence (PL) and Raman spectroscopy. For wide wires (L-x>40 nm), the strain r elaxation results in a redshift of both the energy of the PL signal an d the CdxZn1-xSe LO phonon frequency in the wire region. To model the strain release, theoretical calculations have been performed, minimizi ng the elasticity energy in the wire cross section. A size-dependent s train release, strongly inhomogeneous across the wire cross section, i s obtained. This results in a size-and composition-dependent band-gap shift, which is found to be in good agreement with the experimental da ta. In narrow wires (L-x<30 nm), the Raman data indicate a saturation of the strain release. As a consequence, clear lateral quantization ef fects due to the quasi-one-dimensional carrier confinement are observe d in the PL spectrum, resulting in a blueshift of the PL signal with d ecreasing wire width.