Dao K.A.,Institute of Materials Science IMS |
Nguyen T.D.,Chungnam National University |
Phan A.T.,Institute of Materials Science IMS |
Do H.M.,Institute of Materials Science IMS
Journal of Materials Science: Materials in Electronics | Year: 2013
The nanowires grown on GaAs semiconductor substrate play very important roles in nanoelectronics, optoelectronics, and sensors. The nanowires can be produced by many methods among the existing methods of nanowires growth on GaAs semiconductor, the vapor-liquid-solid (VLS) method appears to be simple, low cost, and popular. However, this method in practice requires further investigations concerning the growth mechanisms, size effects, and the role of Au catalyst metal diffusion, as well as the effect of technological conditions. Several undesired phenomena, which strongly influence the morphologies, features, and applications of the grown nanowires, can occur as the result of using thick Au catalyst layers, high growth temperatures, and/or small vapor volume in the closed ampoule. This paper aims to examine simultaneous formation of voids, etched holes, and GaO particles along with the nanowires grown by VLS method on GaAs substrate. As the result, typical technological conditions for the nanowires growth with better characterizations are proposed. © 2013 Springer Science+Business Media New York.
Trung D.Q.,Hanoi University of Science and Technology |
Tuan N.T.,Hanoi University of Science and Technology |
Chung H.V.,Hanoi University of Science and Technology |
Duong P.H.,Institute of Materials Science IMS |
Huy P.T.,Hanoi University of Science and Technology
Journal of Luminescence | Year: 2014
The optical properties and morphological features of ZnS nanowires fabricated by a thermal evaporation process have been systematically studied. We have observed both ZnS nanowires and ZnO structures in one fabrication batch. One common green emission peak in the photoluminescence spectra centered at 516-520 nm appears and is independent of the don pants of the source materials and the catalytic metals. This peak is attributed to the contribution of ZnO structures by means of X-ray diffraction and Raman spectroscopic analysis. The exponential degradation of the photoluminescence intensity of ZnS and ZnO in air under UV laser irradiation not only indicates the significant role of oxygen diffusing into ZnO structures but also provides additional confirmation regarding the degradation that occurs inside ZnS nanowires. The emission model related to defects and ligand fields that occurs in both ZnS and ZnO as a result of this fabrication approach is discussed. © 2014 Elsevier B.V.