Photoluminescence and Raman analysis of ZnO nanowires deposited on Si(100) via vapor-liquid-solid process

ZnO nanowires were deposited on the Si(1 0 0) substrate via vapor-liquid-solid process with flowing Ar gas current for 90 s. The morphology, structure, and optical properties were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), and Raman spectrum, respectively. The results showed that the as-deposited ZnO nanowires had hexagonal wurzite structure. The Raman spectrum showed oxygen defects in ZnO nanowires due to the existence of the Ar gas during the growth process, leading to the dominant green band peak and the weak UV peak in the PL spectrum. And blue shift of the Raman peaks was attributed to the lattice distortion and piezoelectric effect of the nanostructures. Finally, the biaxial compressive stress within the c-axis oriented ZnO nanowires was estimated to 0.365 GPa, which was also responsible for the frequency shift of the E-2 (high) mode of the Raman spectra. (C) 2007 Elsevier B.V. All rights reserved.