[en] Here we present optical spectroscopy studies to examine structural and optical properties of active region of quantum cascade lasers grown fully by MOCVD technique. The active part is InGaAs/AlInAs based multilayer structure nominally lattice matched to InP substrate. In this communication we study a set of structures with different growth temperature of the cladding layers and its influence on the properties of active core. The x-ray spectroscopy (XRD) allowed to determine the widths of constituent layers and compare obtained values with nominal ones. Fourier-transformed photoluminescence (FTPL) and photoreflectance (PR) measurements provided high signal to noise spectra, proving good optical and structural properties of investigated samples. A model of atoms interdiffusion processes was presented to explain observed small energy shifts of the transitions energies within the investigated multilayer structures. (paper)

[en] In the presented work, the possibility of fabrication of ZnO single- and multi-nanofiber structures using a standard microelectronic device technology were studied. An innovative fabrication step, namely, selective wet chemical nanofibers etching through a photoresist mask, was used to define the active area, along with mesa etch in the Si/SiO₂ substrate. Test structures in the configuration of a resistor and Schottky diode with chemically active electrospun ZnO nanofibers were prepared. The Ti/Au ohmic and Pt Schottky contacts were fabricated using a lift-off photolithography process. Optical and scanning electron microscopy studies were done to characterize ZnO nanofibers and topography of contacts. The measurements made for electrical characterization showed linear I–V dependence and saturation of the current for single ZnO nanofiber structures.