The photoluminescence, photoluminescence excitation, infrared absorption and Raman scattering spectra of as-prepared Si wires, like porous silicon (PSi), are examined in dependence on technological regimes. Atomic force microscopy (AFM) is used for investigation of surface morphology and its connection with the photoluminescence (PL) peculiarities. The experimental data are analyzed from the point of view of new concept of Si wire photoluminescence, based on the electron ballistic effect in photoluminescence excitation of Si/SiO x interface defect-related photoluminescence.